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| I.D | Level | Problem | Problem Topic | Problem Solution | Problem Solver | Solution image |
|---|---|---|---|---|---|---|
| 1 | 11th | A certain horse says, “There’s no use trying to pull that cart. No matter how hard I pull on the cart, it will always pull back on me with exactly the same force. So I can never make it go.” Explain what is wrong with the horse’s reasoning. (Free-body diagrams, showing all the forces involved, will help.) | Force & Laws of Motion | select the link. | JKM | click here |
| 2 | 11th | Does a negative acceleration necessarily imply that a body is slowing down? What (or who) determines the sign if the acceleration in a particular problem? | Force & Laws of Motion | click the link. | JKM | click here |
| 3 | 9th | Chapter 2 page 15 1.what is meant by a pure substance? | Is matter around us pure | Ans. Pure substance is one which is made up of only one kind of particles i.e all constituent particles of a pure substance are the same in their chemical nature. For example, hydrogen is made up of only one kind of particle called hydrogen atoms. Similarly, water is made up of only one kind of particles called water molecules. Thus hydrogen and water are pure substances. | RA | "No image" |
| 4 | 8th | N.C.E.R.T. 07,CHAPTER-2,PAGE-15 Q2. List the points of differences between homogeneous and heterogeneous mixtures. OR N.C.E.R.T 07,CHAPTER-2,PAGE-18 Q1. Differentiate between homogeneous and heterogeneous mixtures with examples. | Is matter around us pure | Select 'click here' to see the solution image. | RA | click here |
| 5 | 8th | N.C.E.R.T 07,CHAPTER 2,PAGE-18 Q2.How are sol,suspension and solution different from each other | Is matter around us pure | Select 'click here' to see the solution image. | RA | click here |
| 6 | 9th | N.C.E.R.T 07,CHAPTER-2,PAGE-18 Q3.To make a saturated solution 36 g of sodium chloride is dissolved in 100 g of water at 293K. Find the concentration at this temperature. | Is matter around us pure | Select 'click here' to see the solution image. | RA | click here |
| 7 | 9th | N.C.E.R.T 07,CHAPTER-2,PAGE-24 Q1. How will you separate a mixture containing kerosene or petrol(difference in their boiling points is more than 25 degree celcius), which are miscible with each other? | Is matter around us pure | Select 'click here' to see the solution image. | RA | click here |
| 8 | 9th | N.C.E.R.T 07, CHAPTER-2, PAGE 24 Q2. Name the technique to separate (i) butter from curd (ii)salt from sea water (iii)camphor from salt | Is matter around us pure | Select 'click here' to see the solution image. | RA | click here |
| 45 | 9th | NCERT 07 page 34 Q.3 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 44 | 9th | NCERT 07 page 34 Q.2 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 43 | 9th | NCERT 07 page 32 Q.1 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 42 | 9th | NCERT 07 page 32 Q.5 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 41 | 9th | NCERT 07 page 32 Q.4 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 40 | 9th | NCERT 07 page 32 Q.3 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 38 | 9th | NCERT 07 page 32 Q.1 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 39 | 9th | NCERT 07 page 32 Q. | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 21 | 9th | NCERT 07,CHAPTER-2,PAGE-24 Q3.What type of mixtures are separated by technique of crystallization? | Is matter around us pure | Click here to view solution | RA | click here |
| 22 | 12th | NCERT 07 page 46 Q1.4 a) Explain the meaning of the statement 'electric charge of a body is quantized'. b) Why can one ignore quantisation of electric charge when dealing with macroscopic i. e. large scale charges? | Electrostatics | a) It is now a well known fact that all charges occuring in nature are positive or negative integral multiples of a basic unit of electric charge which is the magnitude of the charge on an electron. We use the symbol e for the charge on an electron. Hence charge on an electron is -e and that on a proton is +e, while charge on a neutron is zero. Any charged body will have + or - ne charge, where n is an integer. This fact is called the quantization of electric charge. b)At the macroscopic level, one deals with charges that are enormous compared to the magnitude of charge e. Since e=1.6 x 10^-19 C, a charge of magnitude, say, 1 micro C contains about 10^13 times the electronic charge. At this scale, the fact that charge can increase or decrease only in units of e is not very different from saying that charge can take continuous values. Thus, at the macroscopic level, the quantisation of charge has no practical consequence. | JKM | "No image" |
| 23 | 12th | NCERT 07 page 46 Q1.1 - What is the force between 2 small charged spheres having charges of 2 x 10^-7 C and 3 x 10^-7 C placed 30cm apart in air. | Electrostatics | Select "Click here" to see the solution image. | JKM | click here |
| 24 | 12th | NCERT 07 page 46 Q1.2 The electrostatic force on a small sphere of charge 0.4 micro C due to another small sphere of charge -0.8 micro C in air is 0.2 N. (a) What is the distance between the two spheres? (b) What is the force on the second sphere due to the first? | Electrostatics | Select "Click here" to see the solution image. | JKM | click here |
| 25 | 12th | NCERT 07 page46 Q1.3 - Check that the ratio ke^2/G(me)(mp) [where me=mass of electron,and mp=mass of proton.] is dimensioless. Look up a table of physical constants and determine the value of this ratio. What does this ratio signify? | Electrostatics | Select "Click here" to see the solution image. | JKM | click here |
| 26 | 12th | NCERT 07 page46 Q1.5 - When a glass rod is rubbed with a silk cloth, charges appear on both the rod and the cloth. A similar phenomenon is observed with many other pairs of bodies. Explain how this observation is consistent with the law of conservation of charge. | Electrostatics | In these processes charge is neither created nor destroyed. It simply gets transferred from one body to another. Therefore one body has greater positive charge and the other gets a greater negative charge. But, the total charge remains conserved. | JKM | "No image" |
| 27 | 12th | NCERT 07 page46 Q1.6 - Four point charges q1=2 micro C,q2=-5 micro C,q3=2 micro C and q4=-5 micro C are located at the corners of a square of side 10cm. What is the force on a charge of 1 micro C placed at the center of the square? | Electrostatics | The center of the square is at equal distances of 5(root2)from each corner. Since opposite corners have equal charges, forces along both diagonals will be balanced. Therefore the resultant force on the 1 micro C charge at center will be 0. | JKM | "No image" |
| 28 | 12th | NCERT 07 page46 Q1.7 - (a) An electrostatic field line of force is a continuous curve. That is, a field line of force cannot have sudden breaks. Why not? (b) Explain why two field lines of force never cross each other at any point. | Electrostatics | Electrostatic field lines start from a positive charge and end at an negative charge. (They are continuous, because the force is continuous. They dont have sudden breaks, otherwise a moving test charge will have to take jumps.) . (b) Two lines of force do not intersect each other because if they intersect at a point, there will be two directions of field at that point. Since this is impossible they never intersect. | JKM | "No image" |
| 29 | 12th | NCERT 07 page46 Q1.8 - Two point charges qA=3 micro C and qB=-3 micro C are located 20cm apart in vacuum. : (a) What is the electric field at the midpoint O of the line AB joining the two charges? , (b) If a negative test charge of magnitude 1.5x10^-9 micro C is placed at this point, what is the force experienced by the test charge? | Electrostatics | Select "Click here" to see the solution image. | JKM | click here |
| 30 | 12th | NCERT 07 page46 Q1.9 - A system has two charges qA=2.5x10^-7 and qB=-2.5x10^-7 located at points A: (0,0,-15cm) and B: (0,0,+15cm) respectively. What is the total charge and electric dipole moment of the system? | Electrostatics | Select "Click here " to see the solution image. | JKM | click here |
| 31 | 12th | NCERT 07 page46 Q1.10 - An electric dipole with dipole moment 4x10^-9 Cm is aligned at 30 degrees with the direction of a uniform electric field of magnitude 5x10^4 NC^-1. Calculate the magnitude of the torque acting on the dipole. Calculate the magnitude of the torque on the dipole. | Electrostatics | Select "Click here" to see the solution image. | JKM | click here |
| 32 | 12th | NCERT 07 page46 Q1.11 - A polythene piece is rubbed with wool and is found to have a negative charge of 3x10^-7 C. - (a) Estimate the number of electrons transferred(from which to which?) . (b) Is there a transfer of mass from wool to polythene? | Electrostatics | Select "Click here" to see the solution image. | JKM | click here |
| 33 | 12th | NCERT 07 page46 Q 1.12 - ( a ) Two insulated charged copper spheres A and B have their centers separated by a distance of 50cm. What is the mutual force of electrostatic repulsion if the charge on each is 6.5x10^-7 C ? The radii of A and B are negligible compared to the distance of separation. ( b ) What is the force of repulsion if each sphere is charged double the above amount and the distance between them is halved? | Electrostatics | Select "Click here" to see the solution image. | JKM | click here |
| 37 | 9th | NCERT 07 page 32 Q.1 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 46 | 9th | NCERT 07 page 34 Q.4 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 47 | 9th | NCERT 07 page 40 Q.1 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 48 | 9th | NCERT 07 page 40 Q.2 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 49 | 9th | NCERT 07 page 40 Q.3 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 50 | 9th | NCERT 07 page 34 Q.1 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 51 | 9th | NCERT 07 page 32 Q.2 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 52 | 9th | NCERT 07 page103 Q.1 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 53 | 9th | NCERT 07 page103 Q.2 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 54 | 9th | NCERT 07 page171 Q.1 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 55 | 9th | NCERT 07 page171 Q.2 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 56 | 9th | NCERT 07 page43 Q.1 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 57 | 9th | NCERT 07 page43 Q.2 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 58 | 9th | NCERT 07 page43 Q.3 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 59 | 9th | NCERT 07 page43 Q.4 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 60 | 9th | NCERT 07 page96 Q.1 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 61 | 9th | NCERT 07 page96 Q.2 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 62 | 9th | NCERT 07 page96 Q.3 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 63 | 9th | NCERT 07 page96 Q.4 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 64 | 9th | NCERT 07 page96 Q.5 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 65 | 9th | NCERT 07 page96 Q.6 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 66 | 9th | NCERT 07 page43 Q.5 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 67 | 9th | NCERT 07 page48 Q.1 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 68 | 9th | NCERT 07 page48 Q.2 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 69 | 9th | NCERT 07 page48 Q.3 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 70 | 9th | NCERT 07 page48 Q.4 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 71 | 9th | NCERT 07 page48 Q.5 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 72 | 9th | NCERT 07 page48 Q.6 | Algebra | Select 'Click here' to see the solution image. | NJ | click here |
| 73 | 9th | NCERT 07 page 28 Q 4 Q.Explain the following giving examples. (a)saturated solution (b)pure substance (c)colloid (d)suspension | Is matter around us pure | Ans. (a) saturated solution: A solution in which no more solute can be dissolved at that temperature is called a saturated solution. A saturated solution contains maximum amount of solute which can be dissolved in it at that temperature. For example, A maximum of 32 grams of potassium nitrate can be dissolved in 100 grams of water at 20 degree. So, a saturated solution of potassium nitrate at 20 degree contains 32 grams of potassium nitrate in 100 grams of water. In order to see whether a given solution is saturated or not try to add more solute to it keeping the temperature constant. If the solute dissolves then the given solution is unsaturated and if solute doesn’t dissolve it is a saturated solution. (b) refer answer to q1, page 15, chapter-2. (c) A colloid is a kind of solution in which solute particles are bigger in size than a true solution and smaller in size than suspension. A colloid cannot be filtered. It appears to be homogeneous but is actually heterogeneous. The particles of a colloid scatter light. The colloids are quite stable. Its particles do not separate out on keeping. The particles of colloid cannot be seen by naked eye. For example, soap solution. We cannot filter soap solution, soap particles can’t be seen by us, the soap particles do not settle down on keeping and a soap solution will scatter light. (d) A suspension is a heterogeneous mixture in which the small particles of a solid are spread throughout a liquid without dissolving in it. For example, chalk in water, mud in water, sand particles in water. The size of the suspension particles is quite large that they scatter light and can be filtered. Suspension is unstable. The particles of suspension can be seen through naked eye. | RA | "No image" |
| 74 | 9th | NCERT 07 page 29 Q 9 Q.Which of the following will show "Tyndall Effect" (a) salt solution (b) Milk (c) Copper sulphate solution (d) Starch solution | Is matter around us pure | Ans. Tyndall effect is the scattering of light by colloidal particles.Milk and starch solution are colloids so they will show Tyndall effect. Salt solution and copper sulphate solution are true solutions. The particles of true solutions are so small in size that they cannot scatter light and hence do not show tyndall effect | RA | "No image" |
| 75 | 9th | NCERT 07 page47 Q1.13 Q.Two insulated charged copper sphere A and B have their centres separated by a distance of 50 cm have identical sizes. A third sphere of the same size but uncharged is brought in contact with the first, then brought in contact with the second, and finally removed from both. What is the new force of repulsion between A and B? | None | Select 'Click here' to see the solution image. | RA | click here |
| 76 | 12th | NCERT 07 page47 Q1.13 Q.Two insulated charged copper sphere A and B have their centres separated by a distance of 50 cm have identical sizes. A third sphere of the same size but uncharged is brought in contact with the first, then brought in contact with the second, and finally removed from both. What is the new force of repulsion between A and B? | Electrostatics | Select 'Click here' to see the solution image. | JKM | click here |
| 77 | 9th | NCERT 07 page 29 Q 5 Q.Classify the following mixtures as a homogeneous and heterogeneous mixture. soda water, wood, air, soil, vinegar, filtered tea. | Is matter around us pure | Ans Those mixtures in which substances are completely mixed together and are indistinguishable from one another are called homogeneous mixtures. Thus soda water, air and vinegar are homogeneous mixtures. Such mixtures have uniform composition throughout and do not have any visible boundary of separation between its constituents. Heterogeneous mixtures are those in which substances remain separated and one substance spreads throughout another as small particles, droplets or bubbles. Thus wood (has variable composition), soil (mixture of sand and other substances) and filtered tea which appears to be homogeneous but is heterogeneous because it is a colloid (mixture of milk and water) are heterogeneous mixtures. | RA | "No image" |
| 78 | 9th | NCERT 07 page 29 Q 6 Q.How will you confirm that the colorless liquid given to you is‘pure water’? | Is matter around us pure | Ans. Water is a compound. If the given liquid is pure water we cannot separate it into its constituents (hydrogen and oxygen) by any physical method such as filtration, evaporation, distillation, sublimation, etc. A mixture or impure substance can be separated into its constituents by physical processes. Also water has a fixed boiling point of 100 degree under standard atmospheric conditions. If the liquid was not pure water it would have a boiling point other than that of water. | RA | "No image" |
| 79 | 9th | NCERT 07 page 29 Q 7 Q.Which of the following materials fall in the category of a ‘pure substance’? (a)Ice (b) Milk (c) Iron (d) Hydrochloric acid (e) Calcium oxide (f) Mercury (g) Brick (h) Wood (i) air | Is matter around us pure | Ans. A pure substance is made of only one kind of particle. All elements and compounds are pure substances because they contain only one kind of particle i.e. only one kind of atom or molecule. Thus, Iron and Mercury are elements and hence are pure substances and hydrochloric acid and calcium oxide are compounds and therefore are pure substances. Since Ice is solid form of water and water is a pure substance, therefore ice is also a pure substance. On the other hand Milk, wood, brick and air are mixtures. | RA | "No image" |
| 80 | 9th | NCERT 07 page 29 Q 8 Q.Identify the solutions among the following mixtures. (a)soil (b) sea water (c) Air (d) coal (e) soda water. | Is matter around us pure | Ans. Solution is a homogeneous mixture of two or more substances. Its composition is same throughout and there is no visible boundary of separation between its constituents. Thus sea water( solution of salt in water), air ( mixture of gases in which solvent is nitrogen) and soda water ( solution of gas in liquid) are solutions. | RA | "No image" |
| 81 | 9th | NCERT 07 page 28 Q 2 Q.Write steps you would use for making tea.Use the words solution, solvent, solute, dissolve, soluble, insoluble, filtrate and residue | Is matter around us pure | Select 'Click here' to see the solution image. | RA | click here |
| 82 | 12th | NCERT 07 page47 Q1.15 Q.Consider a uniform eletric field E= 3 x 10^3 i N/C . (a) What is the flux if this field passes through a square of 10cm on a side whose plane is parallel to the yz plane ? (b) What is the flux through the same square if the normal to its plane makes a 60 degree angle with the x-axis ? | Electrostatics | Select 'Click here' to see the solution image. | JKM | click here |
| 83 | 12th | NCERT 07 page47 Q 1.16 Q. What is the net flux of the unifrom eletric field E = 3 x 10^3 i N/C through a cube of side 20 cm oriented so that its phases are parallel to the coordinate planes ? | Electrostatics | Zero. The number of lines entering the cube is the same as the number of lines leaving the cube | JKM | "No image" |
| 84 | 12th | NCERT 07 page47 Q 1.17 Q.Careful measurement of the eletric field at the surface of a black box indicates that the net outword flux through the surface of the box is 8.0 x 10^3Nm^2/C . (a) What is the net charge inside the box ? . (b) If the net outword flux through the surface of the box were zero, could you conclude that there were no charges inside the box ?. Why or Why not ?. | Electrostatics | Select 'Click here' to see the solution image. | JKM | click here |
| 85 | 12th | NCERT 07 page48 Q 1.19 Q.A point charge of 2.0 macro C is at the centre of a cubic Gaussian surface 9.0 cm on edge. What is the net eletric flux through the surface ? . | Electrostatics | Select 'Click here' to see the solution image. | JKM | click here |
| 86 | 12th | NCERT 07 page48 Q 1.20 Q.A point charge causes an eletric flux of -1.0 x 10^3 Nm^2 / C to pass through a spherical Gaussian surface of 10.0 cm radius centred on the charge. (a) If the radius of the Gaussian surface were doubled, how much flux would pass through the surface ?. (b) What is the value of the point-charge ?. | Electrostatics | Select 'Click here' to see the solution image. | JKM | click here |
| 87 | 12th | NCERT 07 page48 Q1.21 Q.A conducting sphere of radius 10 cm has an unknown charge. If the eletric field 20 cm from the centre of the sphere is 1.5 x 10^3 N/C and points radially inward. what is the net charge on the sphere ? . | Electrostatics | Select 'Click here' to see the solution image. | JKM | click here |
| 88 | 9th | NCERT 07 page28 Q 1 Q. Which seperation techniques will you apply for the seperation of the following ? (a) Sodium chloride from its solution in water . (b) Ammonium chloride from the mixture containing sodium chloride and ammonium chloride . (c) Small pieces of metal in the engine oil of a car . (d) Different pigments from an extract of flower petals . (e) Butter from curd . (f) Oil from water . (g) Tea leaves from tea. (h) Iron pins from sand . (i) Wheat grains from husk . (j) Fine mud particles suspended in water . | Is matter around us pure | Select 'Click here' to see the solution image. | RA | click here |
| 89 | 9th | NCERT 07 page 28 Q 2 Q. Write the steps you would use for making tea . Use the words solution, solvent,solute,dissolve,soluble,insoluble,filtrate and residue . | Is matter around us pure | Select 'Click here' to see the solution image. | RA | click here |
| 90 | 9th | NCERT 07 page 28 Q 2 Q. Write the steps you would use for making tea . Use the words solution, solvent,solute,dissolve,soluble,insoluble,filtrate and residue . | Is matter around us pure | Select 'Click here' to see the solution image. | RA | click here |
| 91 | 9th | NCERT 07 page 28 Q 2 Q. Write the steps you would use for making tea . Use the words solution, solvent,solute,dissolve,soluble,insoluble,filtrate and residue . | Is matter around us pure | Select 'Click here' to see the solution image. | RA | click here |
| 92 | 12th | NCERT 07 page127 Q 3.1 Q. The storage battery of a car has an emf of 12 V. If the internal resistance of the battery is 0.4 oam, What is the maximum current that can be drawn from the battery ? | Current & Electricity | Select 'Click here' to see the solution image. | JKM | click here |
| 93 | 12th | NCERT 07 page127 Q3.2 Q. A battery of emf 10 V and internal resistance 3 oam is connected to a resistor . If the current in the circuit is 0.5A, what is the resistance of the resistor ? What is the terminal voltage of the battey when the circuit is closed ? | Current & Electricity | Select 'Click here' to see the solution image. | JKM | click here |
| 94 | 12th | NCERT 07 page 127 Q 3.3 Q. (a) Three resistors 1oam 2oam and 3oam are combined in series . What is the total resistance of the combination ? (b) If the combination is connected to a battery of emf 12 V and negligible internal resistance , obtain the potential dorp across each resistor. | Current & Electricity | Select 'Click here' to see the solution image. | JKM | click here |
| 95 | 12th | NCERT 07 page 127 Q 3.4 Q. (a) Three resistors 2oam 4oam and 5oam are combined in parallel . What is the total resistance of the combination ? (b) If the combination is connected to a battery of emf 20 V and negligible internal resistane , determine the current through each resistor and the total current drawn from the battery ? | Current & Electricity | Select 'Click here' to see the solution image. | JKM | click here |
| 96 | 12th | NCERT 07 page 127 Q 3.7 Q. A silver wire has a resistance of 2.1 oam at 27.5 degree celcious , and a resistance of 2.7 oam at 100 degree celcious . Determine the temperature coefficient of resistivity of silver . | Current & Electricity | Select 'Click here' to see the solution image. | JKM | click here |
| 97 | 12th | NCERT 07 page 128 Q 3.10 Q. (a) In a metre bridge as shown in "click here" the balance point is found to be at 39.5 cm from the end A, when the resistor Y is of 12.5 oam . Determine the resistance of X. Why are the connection between resistors in a Wheatstone or metre bridge made of thick copper strips ? | Current & Electricity | Select 'Click here' to see the solution image. | JKM | click here |
| 98 | 12th | NCERT 07 page 127 Q 3.5 Q. At room temperature (27.0 degree C) the resistance of a heating element is 100 ohm What is the temperature of the element if the resistance is found to be 117 ohm , given that the temperature coefficient of the material of the resistor is 1.70 x 10^-4 degree C^-1 . | Current & Electricity | Select 'Click here' to see the solution image. | JKM | click here |
| 99 | 12th | NCERT 07 page 127 Q 3.6 Q. A negligibly small current is passed through a wire of length 15 m and uniform cross-section 6.0 x 10^-7 m^2, and its resistance is measured to be 5.0 ohm. What is the resistivity of the material at the temperature of the experiment ? | Current & Electricity | Select 'Click here' to see the solution image. | JKM | click here |
| 100 | 12th | NCERT 07 page 127 Q 3.8 Q. A heating element using nichrome connected to a 230 V supply draws an initial current of 3.2 A which settles after a few seconds to a steady value of 2.8 A. What is the steady temperature of the heating element if the room temperature is 27.0 degree C ? . Temperature coefficient of resistance of nichrome averaged over the temperature range involved is 1.70 x 10^-4 degree C^-1. | Current & Electricity | Select 'Click here' to see the solution image. | JKM | click here |
| 101 | 12th | NCERT 07 page 128 Q 3.9 Q. Determine the current in each branch of the network shown in the figure at "click here" | Current & Electricity | Select 'Click here' to see the solution image. | JKM | click here |
| 102 | 12th | NCERT 07 page 128 Q 3.11 Q. A storage battery of emf 8.0 V and internal resistance 0.5 ohm is being charged by a 120 V dc supply using a series resistor of 15.5 ohm . What is the terminal voltage of the battery during charging ? What is the purpose of having a series resistor in the charging circuit ? | Current & Electricity | Select 'Click here' to see the solution image. | JKM | click here |
| 103 | 12th | NCERT 07 page 128 Q 3.11 Q. A storage battery of emf 8.0 V and internal resistance 0.5 ohm is being charged by a 120 V dc supply using a series resistor of 15.5 ohm . What is the terminal voltage of the battery during charging ? What is the purpose of having a series resistor in the charging circuit ? | Current & Electricity | Select 'Click here' to see the solution image. | JKM | click here |
| 104 | 12th | NCERT 07 page 128 Q 3.12 Q. In a potentiometer arrangement, a cell of emf 1.25 V gives a balance point at 35.0 cm length of the wire. If the cell is replaced by another cell and the balance point shift to 63.0, What is the emf of the second cell ? | Current & Electricity | Select 'Click here' to see the solution image. | JKM | click here |
| 105 | 12th | NCERT 07 page 128 Q 3.13 Q. The number density of free electrons in a copper conductor estimated in Example 3.1 is 8.5 x 10^28 m^-3. How long does an electron take to drift from one end of a wire 3.0 m long to its other end ? The area of cross-section of the wire is 2.0 x 10^-6 m^2 and it is carrying a current of 3.0 A. | Current & Electricity | Select 'Click here' to see the solution image. | JKM | click here |
| 106 | 12th | NCERT 07 page 129 Q 3.20 Q. (a) Given n resistors each of resistance R , how will you combine them to get the (i) maximum (ii)minimum effective resistance ? What is the ratio of maximum to minimum resistance ? (b) Given the resistance of 1 ohm 2ohm 3ohm how will be combine them to get an equivalent resistance of (i) (11/3)ohm ,(ii) (11/5) ohm , (iii) 6 ohm , (iv) (6/11) ohm ? (c) Determine the equivalent resistance of network shown in "click here" | Current & Electricity | Select 'Click here' to see the solution image. | JKM | click here |
| 107 | 12th | NCERT 07 page 130 Q 3.21 Q. Determine the current drawn from a 12 V supply with internal resistance 0.5 ohm by the infinite network shown in figure "click here" . Each resistor has 1 ohm resistance . | Current & Electricity | Select 'Click here' to see the solution image. | JKM | click here |
| 108 | 12th | NCERT 07 page 169 Q 4.1 Q. A circular coil of wire consisting of 100 turns,each of radius 8.0cm carries a current of 0.40 A. What is the magnetude of the magnetic field B at the center of the coil ? | 10th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 109 | 12th | NCERT 07 page 169 Q 4.2 Q. A long straight wire a current of 35 A. What is the magnitude of the field B at a point 20 cm from the wire ? | 10th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 110 | 12th | NCERT 07 page 169 Q 4.4 Q. A horizontal overhead power line carries a current of 90 A in east to west direction. What is the magnitude and direction of the magnetic field due to the current 1.5 m below the line ? | 10th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 112 | 12th | NCERT 07 page 169 Q 4.5 Q. What is the magnitude of magnetic force per unit lenght on a wire carrying a current of 8A and making as angle of 30^o with the direction of a uniform magnetic field of 0.15 T ? | 10th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 113 | 12th | NCERT 07 page 169 Q 4.6 Q. A 3.0 cm wire carrying a current of 10 A is placed inside a solenoid perpendicular to its axis. The magnetic field inside the solenoid is given to be 0.27 T. What is the magnetic force on the wire ? | 10th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 114 | 12th | NCERT 07 page 169 Q 4.7 Q. Two long and parallel straight wires A and B carrying currents of 8.0 A and 5.0 A in the same direction are seperated by a distance of 4.0 cm. Estimate the force on a 10 cm section of wire A ? | 10th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 115 | 12th | NCERT 07 page 169 Q 4.8 Q. A closely wound solenoid 80 cm long has 5 layers of windings of 400 turns each . The diameter of the solenoid is 1.8 cm . If the current carried is 8.0 A , estimate the magnitude of B inside the solenoid near its centre. | 10th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 116 | 12th | NCERT 07 page 169 Q 4.9 Q. A square coil of side 10 cm consist of 20 turns and carries a current of 12 A . The coil is suspended vertically and the normal to the plane of the coil makes an angle of 30^0 with the direction of a uniform horizontal magnetic field of magnetude 0.80 T . What is the magnitude of torque experienced by the coil ? | 10th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 117 | 12th | NCERT 07 page169 Q 4.10 Q. Two moving coil meters M1 and M2 have the following particulars: R1= 10 ohm , N1 = 30, A1 = 3.6 x 10^-3 m^2 B1= 0.25 T, R2 = 14 ohm, N2 = 42, A2= 1.8 x 10^-3 m^2, B2= 0.50 T, (The spring constants are identical for the two meters). Determine the ratio of (a) current sensitivity and (b) voltage sensitivity of M2 and M1. | 10th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 118 | 12th | NCERT 07 page 169 Q 4.11 Q. In a chamber, a uniform magnetic field of 6.5 G (1 G =10^-4 T ) is maintained. An electron is shot into the field with a speed of 4.8 x 10^6 ms^-1 normal to the field. Explain why the path of the electron is a circle. Determine the radius of the circular orbit. (e = 1.6 x 10^-19 C, me = 9.1 x 10^-31 kg) | 10th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 119 | 12th | NCERT 07 page 169 Q 4.13 Q. (a) A circular coil of 30 turns and radius 8.0 cm carrying a current of 6.0 A is suspended vertically in a uniform horizontal magnetic field of magnitude 1.0 T. The filed lines make an angle of 60^o with the normal of the coil . Calculate the magnitude of the counter torque that must be applied to prevent the coil from the turning. (b) Would your answer change if the circular coil in (a) were replaced by a planar coil of some irregular shape that encloses the same area ? ( All other particulars are also unaltered. ) | 10th physics | Select 'Click here' to see the solution image | JKM | click here |
| 120 | 12th | NCERT 07 page 170 Q 4.14 Q. Two concentric circular coils X and Y of radii 16 cm and 10 cm respectively lie in the same vertical plane containing the north to south direction. Coil X has 20 turns and carries a current of 16 A; Coil Y has 25 turns and carries a current of 16 A; Coil Y has 25 turns and carries a current of 18 A. The sense of the current in X is anticlock-wise, and in Y clockwise, for an observer looking at the coils facing west. Give the magnitude and direction of the net magnetic field due to the coils at their centre. | 10th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 121 | 12th | NCERT 07 page 170 Q 4.15 Q. A magnetic field of 100 G (1 G = 10^-4T ) is required which is uniform in a region of linear dimension about 10 cm and area of cross section about 10^-3 m^2. The maximum current-carrying capacity of a given coil of wire is 15 A and the number of turns per unit length that can be wound round a core is at most 1000 turns m^-1. Suggest some appropriate design particulars of a solenoid for the required purpose. Assume the core is not ferromagnetic. | 10th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 122 | 12th | NCERT 07 page 170 Q:4.16 Q. For a circular coil of radius R and N turns carrying current I, the magnitude of the magnetic field at a point on its axis at a distance x from the centre is given by macro 0 IR^2 N B=--------------- 2(x^2 + R^2)^3/2 (a) Show that this reduces to the standard result for field at the centre of the coil. (b) Consider two parallel coaxial circular coils of equal radius R , and number of turns N , carrying equal currents inthe same direction , and separated by a distance R . Show that the field on the axis around the midpoint between the coilis uniform over a distance that is small compared to R , and is given by macro 0 NI B= 0.72---------- approximately R (Such an arrangement to produce a nearly uniform magnetic field over a small region is known as Helmholtz coils ) | 10th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 123 | 12th | NCERT 07 page 170 Q 4.17 Q. A toroid has a core (non-ferromagnetic) of inner radius 25 cm and outer radius 26 cm , around which 3500 turns of a wire are wound . If the current in the wire is 11 A , What is the magenetic field (a) Outside the toroid, (b) Inside the core of the toroid , and (c) in he empty space surrounded by the toroid. | 10th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 124 | 12th | NCERT 07 page170 Q 4.18 Q. Answer the following questions: (a) A magnetic field that varies in magenitude from point to point but has a constant direction ( east to west ) is set up in the champer.A charge particle enters the chamber and travels undefeated along a straight path with constant speed . What can you say about the initial velocity of the particle ? (b) A charged particle enters an environment of a strong and non-uniform magnetic field varying from point to point both in magnitude and direction , and comes out of it following a complicated trajectory . Would its final speed equal the initial speed if it suffered no collisions with the environment ? (c) An electron travelling west to east enters a chamber having a uniform electrostatic field in north to south direction . Specify the direction in which a uniform magnetic field should be set up to prevent the electron from deflecting from its straight line path. | 10th physics | (a) initial V is either parallel or anti-parallel to B. (b) Yes, because magnetic force can change the direction of V, not its magnitude . (c) B should be in a vertically downward direction. | JKM | "No image" |
| 125 | 12th | NCERT 07 page 171 Q 4.19 Q. An electron emited by a heated cathode and acceletated through a potential difference of 2.0 kv , enters a region with uniform magnetic field of 1.05 T . Determine the trajectory of the electron if the field (a) is transverse to its initial velocity, (b) makes an angle of 30^0 with initial velocity. | 10th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 126 | 12th | NCERT 07 page 171 Q 4.20 Q. A mgnetic field set up using Helmholtz coil ( Such an arrangement to produce a nearly uniform magnetic field over a small region ) is uniform in a small region and has a manitude of 0.75 T . In the same region , a uniform electrostatic field is maintained in a direction normal to the common axis to the coils. A narrow beam of ( singlespecies ) charged particles all accelerated through 15 KV enters this region in a direction perpendicular to both the axis of the coils and the electrostatic field. If the beam remains undeflected when the electrostatic field is 9.0 x 10^5 V m^-1 , make a simple guess as to what the beam contains . Why is the answer not unique ? | 10th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 127 | 12th | NCERT 07 page 171 Q 4.21 Q. A straight horozontal conducting rod of length 0.45 m and mass 60 g is suspended by two vertical wires at its ends. A current of 5.0 A is set up in the rod through the wires. (a) What magnetic field should be set up normal to the conductor in order that the tension in the wires is zero. (b) What will be the total tension in the wires if the direction of current is reversed keeping the magnetic field same as before . ( ignore the mass of the wires. ) g = 9.8 ms^-2 | 10th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 128 | 12th | NCERT 07 page 171 Q 4.22 Q. The wires which connect the battery of an automobile to its starting motor , carry a current of 300 A ( for a short time). What is the force per unit length between the wires if they are 70 cm long and 1.5 cm apart ? Is the force attractive or repulsive ? | 10th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 129 | 12th | NCERT 07 page 171 Q 4.23 Q. A uniform magnetic field of 1.5 T exists in a cylindrical region of radius 10.0 cm , its direction parallel to the axis along east to west . A wire carrying current of 7.0 A in the north to south direction passes through this region . What is the magnitude and direction of the force on the wire , if (a) the wire intersects the axis , (b) the wire is turned from N-S to northeast-southwest direction , (c) the wire in the N-S direction is lowered from the axis by a distance of 6.0 cm ? | 10th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 130 | 12th | NCERT 07 page 171 Q 4.24 Q. A uniform magnetic field of 3000 G is established along the positive Z-direction . A rectangular loop of sides 10 cm and 5 cm carries a current of 12 A . What is the torque on the loop in the different cases shown in the figure ? What is the force on each case ? Which case corresponds to stable equilibrium ? ( The figure is shown in "click here" ) | 10th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 131 | 12th | NCERT 07 page 172 Q 4.25 Q. A circular coil of 20 turns and radius 10 cm is placed in a uniform magnetic field of 0.10 T normal to the plane of the coil . If the current in the coil is 5.0 A , What is the (a) total torque on the coil , (b) total force on the coil , (c) average force on each electron in the coil due to the magnetic field ( the coil is made of copper wire of cross-sectional area 10^-5 m^2 , and the free electron density of copper is given to be about 10^29 m^-3 .) | 10th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 132 | 12th | NCERT 07 page 171 Q 4.26 Q. A solenoid 60 cm long and of radius 4.0 cm has 3 layers of windings of 300 turns each . A 2.0 cm long wire of mass 2.5g lies inside the solenoid ( near its centre ) normal to its axis : both the wire and the axis of the solenoid are in the horizontal plane . The wire is connected through two leads parallel to the axis of the solenoid to an external battery , Which supplies a current of 6.0 A in the wire . What value of current ( with appropriate sense of circulation ) in the winding of the solenoid can support the weight of the wire ? g = 9.8 ms^-2. | 10th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 133 | 12th | NCERT 07 page 200 Q 5.1 Q. Answer the following questions regarding earth's magnetism. (a) A vector needs three quantities for its specification. Name the three independent quantities conventionally used to specify the earth's magnetic field. (b) The angle of dip at a location in southern India is about 18^o . Would you expect a greater or smaller dip angle in Britain ? (c) If you made a map of magnetic field lines at Melbourne in Australia , would the lines seem to go into the ground or come out of the ground ? (d) In which direction would a compass free to move in the vertical plane point to , if located right on the geomagnetic north or south pole ? (e) The earths field , it is claimed , roughly approximates the field due to a dipole of magnetic moment 8 x 10^22 J T^-1 located at its centre. Check the order of magnitude of this number in some way. (F)Geologists claim that besides the main magnetic N-S poles , there are several local poles on the earth's surface oriented in different directions . How is such a thing possible at all ? | 9th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 134 | 12th | NCERT 07 page 200 Q 5.1 Q. Answer the following questions regarding earth's magnetism. (a) A vector needs three quantities for its specification. Name the three independent quantities conventionally used to specify the earth's magnetic field. (b) The angle of dip at a location in southern India is about 18^o . Would you expect a greater or smaller dip angle in Britain ? (c) If you made a map of magnetic field lines at Melbourne in Australia , would the lines seem to go into the ground or come out of the ground ? (d) In which direction would a compass free to move in the vertical plane point to, if located right on the geomagnetic north or south pole ? (e) The earth's field, it is claimed , roughly approximates the field due to a dipole of magnetic moment 8 x 10^22 J T^-1 located at its centre. Check the order of magnitude of this number in some way. (f) Geologits claim that besides the main magnetic N-S poles, there are several local poles on the earths surface oriented in different direction. How is such a thing possible at all ? | 9th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 135 | 12th | NCERT 07 page 200 Q 5.2 Q. Answer the following questions: (a) The earth's magnetic field varies from point to point in space. Does it also change with time ? If so, on what time scale does it change appreciably ? (b) The earth's core is known to contain iron. Yet geologist do not regard this as a source of the earth's magnetism. why ? (c) The charged currents in the outer conducting regions of the earth's core are thought to be responsible for earth's magnetism . What might be the 'battery'(i.e. the source of energy) to sustain these currents ? (d) The earth may have even reversed the direction of its field several times during its history of 4 to 5 billion years. How can geologists know about the earth's field in such distant past ? (e) The earth's field departs from its dipole shape substantially at large distances (greater than about 30000 km ). What agencies may be responsible for this distortion ? (f) Interstellar space has an extremely weak magnetic field of the order of 10^-12 T. Can such a weak field be of any significant consequence ? Explain. [ Note: Exercise 5.2 is meant mainly to aruse your curiosity. Answer to some questions above are tentative or unknown. Brief answers wherever possible are given at the end. For details, you should consult a good text on geomagnetism ] | 9th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 136 | 12th | NCERT 07 page 200 Q 5.3 Q. A short bar magnet placed with its axis at 30^o with a uniform external magnetic field of 0.25 T experiences a torque of magnitude equal to 4.5 x 10^-2 J. What is the magnitude of magnetic moment of the magnet ? | 9th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 137 | 12th | NCERT 07 page 200 Q 5.4 Q. A short bar magnet of magnetic moment m = 0.32 JT^-1 is placed in a uniform external magnetic field of 0.15 T. If the bar is free to rotate in the plane of the field , which orientation would correspond to its (i) stable and (ii) unstable equilibrium ? What is the potential energy of the magnet in each case ? | 9th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 138 | 12th | NCERT 07 page 201 Q 5.5 Q. A closely wound solenoid of 800 turns and area of cross-section 2.5 x 10^-4 m^2 carries a current of 3.0 A. Explain the sense in which the solenoid acts like a bar magnet. What is its associated magnetic moment ? | 9th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 139 | 9th | NCERT 07 page 28 Q 1 Q. Which separation technique will you apply for the separation of the following ? (a) Sodium Chloride from its solution in water. (b) Ammonium Chloride from a mixture containing sodium chloride and ammonium chloride. (c) Small pieces of metal in the engine oil of a car. (d) Different pigments from an extract of flower petals. (e) Butter from curd. (f) Oil from water. (g) Tea leaves from tea. (h) Iron pins from sand. (i) Wheat grains from husk. (j) Fine mud particles suspended in water. | Is matter around us pure | Select 'Click here' to see the solution image. | JKM | click here |
| 140 | 9th | NCERT 07 page 28 Q 3 Q. Pragya tested the solubility of three different substances at different temperatures and collected the data as given below (results are given in the table at "click here" , as grams of substances dissolved in 100 grams of water to form a saturated solution). (a) What mass of potassium nitrate would be needed to produce a saturated solution of potassium nitrate in 50 grams of water at 313 K ? (b) Pragya makes a saturated solution of potassium chloride in water at 353 K and leaves the solution to cool at room temperature . What would she observe as the solution cools ? Explain. (c) Find the solubility of each salt at 293 K . Which salt has the highest solubility at this temperature ? (d) What is the effect of change of temperature on the solubility of a salt ? | Is matter around us pure | Select 'Click here' to see the solution image. | RA | click here |
| 141 | 9th | NCERT 07 page 43 Q 1 Q. A 0.24 g sample of compound of oxygen and boron was found by analysis to contain 0.096 g of boron and 0.144 g of oxygen . Calculate the percentage composition of the compound by weight. | Atoms and Molecules | Select 'Click here' to see the solution image. | RA | click here |
| 142 | 9th | NCERT 07 page 43 Q 1 Q. A 0.24 g sample of compound of oxygen and boron was found by analysis to contain 0.096 g of boron and 0.144 g of oxygen . Calculate the percentage composition of the compound by wieght. | Atoms and Molecules | Select 'Click here' to see the solution image. | RA | click here |
| 143 | 9th | NCERT 07 page 44 Q 3 Q. What are polyatomic ions ? Give example . | Atoms and Molecules | Select 'Click here' to see the solution image. | RA | click here |
| 144 | 9th | NCERT 07 page 43 Q 2 Q. When 3.0 g of carbon is burnt in 8.00 g oxygen . 11.00 g of carbon dioxide is produced . What mass of carbon dioxide will be formed when 3.00 g of carbon is burnt in 50.00 g of oxygen ? Which law of chemical combination will govern your answer ? | Atoms and Molecules | Select 'Click here' to see the solution image. | RA | click here |
| 145 | 9th | NCERT 07 page 44 Q 4 Q. Write the chemical formula of the following (a) Magnesium Chloride (b) Calcium oxide (c) Copper nitrate (d) Aluminium Chloride (e) Calcium Carbonate | Atoms and Molecules | Select 'Click here' to see the solution image. | RA | click here |
| 146 | 9th | NCERT 07 page 44 Q 6 Q. Calcuate the molar mass of the following substances. (a) Ethyne , C2 H2 (b) Sulpher molecule , S8 (c) Phosphorus molecule, P4 (Atomic mass of phosphorus = 31) (d) Hydrochloric acid, HCI (e) Nitric acid, HNO3 | Atoms and Molecules | Select 'Click here' to see the solution image. | RA | click here |
| 147 | 12th | NCERT 07 page 201 Q 5.7 Q. A bar magnet of magnetic moment 1.5 J T^-1 lies aligned with the direction of a uniform magnetic field of 0.22 T. (a) What is the amount of work required by an external torque to turn the magnet so as to align its magnetic moment (i) Normal to the field dirction (ii) Opposite to the field direction (b) What is the torque on the magnet in cases (i) and (ii) ? | 9th physics | Select 'Click here' to see the solution image | JKM | click here |
| 148 | 12th | NCERT 07 page 201 Q 5.8 Q. A closely wound solenoid of 2000 turns and area of cross-section 1.6 x 10^-4 M^2 , carrying a current of 4.0 A is suspended through its centre allowing it to turn in a horizontal plane. (a) What is the magnetic moment associated with the solenoid (b) What is the force and torque on the solenoid if a uniform horizontal magnetic field of 7.5 x 10^-2 T is set up at an angle of 30^o with the axis of the solenoid ? | 9th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 149 | 12th | NCERT 07 page 201 Q 5.10 Q. A magnetic needle free to rotate in a vertical plane parallel to the magnetic meridian has its north tip pointing down at 22^o with the horizontal . The horizontal component of the earths magnetic field at the place is known to be 0.35 G . Determine the magnetude of the earth's magnetic field at the location ? | 9th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 150 | 12th | NCERT 07 page 201 Q 5.11 Q. At a certain location in Africa , a compass point 12^o West of the geographic north . The north tip of the magnetic needle of a dip circle placed in the plane of magnetic meridian points 60^o above the horizontal . The horizontal component of the earth's field is measured to be 0.16 G. Specify the direction and magnitude of the earth's field at the location . | 9th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 151 | 12th | NCERT 07 page 201 Q 5.12 Q. A short bar magnet has a magnetic moment of 0.48 J T^-1 . Give the direction and magnitude of the magnetic field produced by the magnet at a distance of 10 cm from the centre of the magnet on (a) the axis (b) the equatorial lines (normal bisector) of the magnet . | 9th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 152 | 12th | NCERT 07 page 201 Q 5.13 Q. A short bar magnet placed in a horizontal plane has its axis aligned along the magnetic north-south dirction. Null points are found on the axis of the magnet at 14 cm from the centre of the magnet. The earth's magnetic field at the place is 0.36 G and the angle of dip is zero . What is the total magnetic field on the normal bisector of the magnet at the same distance as the null-points (i.e. 14 cm) from the centre of the magnet. | 9th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 153 | 12th | NCERT 07 page 201 Q 5.14 Q. A short bar magnet placed in a horizontal plane has its axis aligned along the magnetic north-south direction. Null points are found on the axis of the magnet at 14 cm form the centre of the magnet . The earth's magnetic field at the place is 0.36 G and the angle of dip is zero. The bar magnet is turned around by 180^o ; Where will be the new null points be located ? | 9th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 154 | 12th | NCERT 07 page 202 Q 5.15 Q. A short bar magnet of magnetic moment 5.25 x 10^-2 J T^-1 is placed with its axis perpendicular to the earth's field direction . At what distance from the centre of the magnet , the resultant field is inclined at 45^o with the earth's field on (a) its normal bisector and (b) its axis. N.L. Magnitude of the earth's field at the place is given to be 0.42 G. Ignore the length of the magnet in comparison to the distances involved. | 9th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 155 | 12th | NCERT 07 page 201 Q 5.9 Q. A circular coil of 16 turns and radius 10 cm carrying a current of 0.75 A rest with its plane normal to an external field of magnitude 5.0 x 10^-2 T . The coil is free to turn about an axis in its plane perpenducular to the field direction. When the coil is turned slightly and released , it oscillates about its stable equilibrium with a freequency of 2.0 s^-1. What is the moment of intertia of the coil about its axis of rotation ? | 9th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 156 | 12th | NCERT 07 page 202 Q 5.18 Q. A long straight horizontal cable carries a current of 2.5 A in the direction 10^o south of west to 10^o north of east. The magnetic meridian of the place happens to be 10^o west of geographical meridian. The earth's magnetic field at the location is 0.33 G, and the angle of dip is zero. Locate the line of neutral points (Ignore the thickness of the cable). | 9th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 157 | 12th | NCERT 07 page202 Q 5.19 Q. A telephone cable at a place has four long straight horizontal wires carrying a current of 1.0 A in the same dirction east to west. The earth's magnetic field at the place is 0.39 G, and the angle of dip is 35^o . The magnetic declination is nearly zero. What are the resultant magnetic fields at points 4.0 cm below the cable ? | 9th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 158 | 12th | NCERT 07 page203 Q 5.20 Q. A compass needle free to turn in a horizontal plane is placed at the centre of circular coil of 30 turns and radius 12 cm . The coil is in a vertical plane making an angle of 45^o with the magnetic meridian . When the current in the coil is 0.35 A, the needle points west to east. (a) Determine the horizontal component of the earth's magnetic field at the location. (b) Magnetic field arises due to charges in motion. Can a system have magnetic moments even though its net charges is zero ? (c) Magnetic force is always normal to the velocity of a charge and therefore does no work. A iron nail held near a magnet , when released , increases its kinetic energy as it moves to cling to the magnet. What agency is responsible for this increase in kinetic energy if not the magnetic field ? | 9th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 159 | 12th | NCERT 07 page 203 Q 5.21 Q. A magnetic dipole is under the influence of two magnetic fields. The angle between the fields direction is 60^o , and one of the fields has a magnitude of 1.2 x 10^-2 T. If the dipole comes to stable equilibrium at an angle of 15^o with this field, what is the magnitude of the other field ? | 9th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 160 | 12th | NCERT 07 page203 Q 5.22 Q. A monoaminergic (18 keV)electron beam initially in the horizontal direction is subject to a horizontal magnetic field of 0.40 G normal to the initial direction . Estimate the up or down deflection of the beam over a distancce of 30 cm (me = 9.11 x 10^-31 kg , e = 1.60 x 10^-19 C) [Note : Data in this exercise are so chosen that the answer will give you an idea of the effect of earth's magnetic field on the motion of the electron beam from the electron gun to the screen in a J.V. set] | 9th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 161 | 12th | NCERT 07 page203 Q 5.22 Q. A monoaminergic (18 keV)electron beam initially in the horizontal direction is subject to a horizontal magnetic field of 0.40 G normal to the initial direction . Estimate the up or down deflection of the beam over a distancce of 30 cm (me = 9.11 x 10^-31 kg , e = 1.60 x 10^-19 C) [Note : Data in this exercise are so chosen that the answer will give you an idea of the effect of earth's magnetic field on the motion of the electron beam from the electron gun to the screen in a J.V. set] | 9th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 162 | 12th | NCERT 07 page 203 Q 5.23 Q. A sample of paramagnetic salt contains 2.0 X 10^24 atomic dipoles each of dipole moment 1.5 x 10^-23 J T^-1. The sample is placed under a homogeneous magnetic field of 0.84 T, and cooled to a temperature of 4.2 K. The degree of magnetic saturation achieved is equal to 15%. What is the total dipole moment of the sample for a magnetic field of 0.98 T and a temperature of 2.8 K? ( Assume Curie's Law) | 9th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 163 | 12th | NCERT 07 page 203 Q 5.24 Q. A Rowland ring of mean radius 15 cm has 3500 turns of wire wound on a ferromagnetic core of relative permeability 800. What is the magnetic field (B) in the core for a magnetising current of 1.2 A ? | 9th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 164 | 12th | NCERT 07 page 203 Q 5.25 Q. The magnetic moment vectors 'micro s' and 'micro l'associated with the intrinsic spin angular momentum S and orbital angular momentum lrespectively of an electron are predicted by quantum theory (and veryfied experimentally to a high accuracy ) to be given by micro s = -(e/m) S, Micro l= -(e/2) l Which of these relations is an accordance with the result expected 'classically' ? Outline the derivation of the classical result. | 9th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 165 | 12th | NCERT 07 page 202 Q 5.16 Q. Answer the following questions: (a) Why does a paramagnetic sample display greater magnetization (for the same magnetizing field ) when cooled ? (b) Why is diamagnetism , in contrast , almost independent of temperature ? (c) If a toroid uses bismuth for its core , will the field in the core be (slightly) greater or (slightly) less than when the core is empty ? (d) Is the permeability of a ferromagnetic material independent of the magnetic field ? If not , is it more for lower or higher fields ? (e) Magnetic field lines are always nearly normal to the surface of a ferromagnet at every point . (This fact is analogous to the static electric field lines being normal to the surface of the conductor at every point ). Why ? (f) Would the maximum possible magnetization of a paramagnetic sample be of the same order of magnitude as the magnetization of a ferromagnet ? | 9th physics | Select 'Click here' to see the solution image. | JKM | click here |
| 166 | 12th | NCERT 07 page 202 Q 5.17 Q. Answer the following questions: (a) Explain qualitatively on the basis of domain picture the irreversibility in the magnetization curve of a ferromagnet. (b) The hysteresis loop of a soft iron piece has much smaller area than that of a carbon steel piece. If the material is to go through repeated cycles of mangetisation , which piece will dissipate greater heat energy ? (c) 'A system displaying a hysteresis loop such as a ferromagnet is a device for storing memory ? ' Explain the meaning of this statement. (d) What kind of ferromagnetic material is used for coating magnetic tapes in a cassette player, or for building 'memory stores' in a modern computer ? (e) A certain region of space is to be shielded from magnetic fields. Suggest a method . | 9th physics | Select 'Click here' to see the solution image. | JKM | click here |