Practice Question Papers · with Answers

CBSE / NCERT Class 11 Physics Practice Question Papers

Download free CBSE / NCERT Class 11 Physics practice question papers with full answer keys. These are original Brain Grain model papers — built from our verified question bank to the real exam blueprint (sections, marks and solutions) — perfect for board revision and model tests.

Brain Grain · braingrain.in
Physics — Practice Paper · Set 1
Class: 11CBSE / NCERTMax Marks: 34
Name: ____________________Reg No: ____________
Part I — Multiple Choice Questions 6 × 1 = 6

Choose the correct answer. (Answer all questions.)

1.One end of a string of length l is connected to a particle of mass m and the other to a small peg on a smooth horizontal table. If the particle moves in a circle with speed v the net force on the particle (directed towards the centre) is : T is the tension in the string. [Choose the correct alternative].i. Tii. T - mv^2/liii. T + mv^2/liv. 0[1]
2.A body is moving unidirectionally under the influence of a source of constant power. Its displacement in time t is proportional toi. t^(1/2)ii. tiii. t^(3/2)iv. t^2[1]
3.Two identical ball bearings in contact with each other and resting on a frictionless table are hit head-on by another ball bearing of the same mass moving initially with a speed V. If the collision is elastic, which of the following (Fig. 5.14) is a possible result after collision ?i. Ball 1 stops and balls 2 and 3 move together with speed V/2.ii. Balls 1 and 2 stop and ball 3 moves with speed V.iii. All three balls move together with speed V/3.[1]
4.In the following two exercises, choose the correct answer from among the given ones: The gravitational intensity at the centre of a hemispherical shell of uniform mass density has the direction indicated by the arrow (see Fig 7.11) (i) a, (ii) b, (iii) c, (iv) 0.i. aii. biii. civ. 0[1]
5.If, in Exercise 4.21, the speed of the stone is increased beyond the maximum permissible value, and the string breaks suddenly, which of the following correctly describes the trajectory of the stone after the string breaks :a. the stone moves radially outwardsb. the stone flies off tangentially from the instant the string breaksc. the stone flies off at an angle with the tangent whose magnitude depends on the speed of the particle ?[1]
6.A body is initially at rest. It undergoes one-dimensional motion with constant acceleration. The power delivered to it at time t is proportional toi. t^(1/2)ii. tiii. t^(3/2)iv. t^2[1]
Part II — Short Answer Questions 14 × 2 = 28

Answer briefly. (Answer all questions.)

7.Two stars each of one solar mass (= 2×1030 kg) are approaching each other for a head on collision. When they are a distance 109 km, their speeds are negligible. What is the speed with which they collide ? The radius of each star is 104 km. Assume the stars to remain undistorted until they collide. (Use the known value of G).[2]
8.Torques of equal magnitude are applied to a hollow cylinder and a solid sphere, both having the same mass and radius. The cylinder is free to rotate about its standard axis of symmetry, and the sphere is free to rotate about an axis passing through its centre. Which of the two will acquire a greater angular speed after a given time.[2]
9.Read each statement below carefully and state, with reasons and examples, if it is true or false : A scalar quantity is one that (a) is conserved in a process (b) can never take negative values (c) must be dimensionless (d) does not vary from one point to another in space (e) has the same value for observers with different orientations of axes.[2]
10.An oxygen cylinder of volume 30 litre has an initial gauge pressure of 15 atm and a temperature of 27 °C. After some oxygen is withdrawn from the cylinder, the gauge pressure drops to 11 atm and its temperature drops to 17 °C. Estimate the mass of oxygen taken out of the cylinder (R = 8.31 J mol–1 K–1, molecular mass of O2 = 32 u).[2]
11.A car weighs 1800 kg. The distance between its front and back axles is 1.8 m. Its centre of gravity is 1.05 m behind the front axle. Determine the force exerted by the level ground on each front wheel and each back wheel.[2]
12.A person trying to lose weight (dieter) lifts a 10 kg mass, one thousand times, to a height of 0.5 m each time. Assume that the potential energy lost each time she lowers the mass is dissipated. (a) How much work does she do against the gravitational force ? (b) Fat supplies 3.8 × 107J of energy per kilogram which is converted to mechanical energy with a 20% efficiency rate. How much fat will the dieter use up?[2]
13.Two ideal gas thermometers A and B use oxygen and hydrogen respectively. The following observations are made : Temperature Pressure thermometer A Pressure thermometer B Triple-point of water 1.250 × 105 Pa 0.200 × 105 Pa Normal melting point of sulphur 1.797 × 105 Pa 0.287 × 105 Pa (a) What is the absolute temperature of normal melting point of sulphur as read by thermometers A and B ? (b) What do you think is the reason behind the slight difference in answers of thermometers A and B ? (The thermometers are not faulty). What further procedure is needed in the experiment to reduce the discrepancy between the two readings ?[2]
14.Find the components along the x, y, z axes of the angular momentum l of a particle, whose position vector is r with components x, y, z and momentum is p with components px, py and pz. Show that if the particle moves only in the x-y plane the angular momentum has only a z-component.[2]
15.The Sun is a hot plasma (ionized matter) with its inner core at a temperature exceeding 107 K, and its outer surface at a temperature of about 6000 K. At these high temperatures, no substance remains in a solid or liquid phase. In what range do you expect the mass density of the Sun to be, in the range of densities of solids and liquids or gases ? Check if your guess is correct from the following data : mass of the Sun = 2.0 ×1030 kg, radius of the Sun = 7.0 × 108 m.[2]
16.A trolley of mass 300 kg carrying a sandbag of 25 kg is moving uniformly with a speed of 27 km/h on a frictionless track. After a while, sand starts leaking out of a hole on the floor of the trolley at the rate of 0.05 kg s–1. What is the speed of the trolley after the entire sand bag is empty ?[2]
17.At what temperature is the root mean square speed of an atom in an argon gas cylinder equal to the rms speed of a helium gas atom at – 20 °C ? (atomic mass of Ar = 39.9 u, of He = 4.0 u).[2]
18.For the travelling harmonic wave y(x, t) = 2.0 cos 2π (10t – 0.0080 x + 0.35) where x and y are in cm and t in s. Calculate the phase difference between oscillatory motion of two points separated by a distance of (a) 4 m, (b) 0.5 m, (c) λ/2, (d) 3λ/4[2]
19.Give the location of the centre of mass of a (i) sphere, (ii) cylinder, (iii) ring, and (iv) cube, each of uniform mass density. Does the centre of mass of a body necessarily lie inside the body ?[2]
20.The photograph of a house occupies an area of 1.75 cm2 on a 35 mm slide. The slide is projected on to a screen, and the area of the house on the screen is 1.55 m2. What is the linear magnification of the projector-screen arrangement.[2]
🔑 Show Answer Key — Set 1
  1. 1. (i) $T$ .
  2. 2. (iii) $t^{3/2}$ .
  3. 3. (ii).
  4. 4. (iii) c.
  5. 5. (b) the stone flies off tangentially from the instant the string breaks.
  6. 6. (ii) $t$ .
  7. 7. Each star collides with speed about $2.6\times10^6\,\text{m s}^{-1}$ ; their relative speed is about $5.2\times10^6\,\text{m s}^{-1}$ .
  8. 8. The solid sphere will acquire the greater angular speed.
  9. 9. a. False; b. False; c. False; d. False; e. True.
  10. 10. $0.14\,\text{kg}$ approximately.
  11. 11. Each front wheel: about $3.68\times10^3\,\text{N}$ . Each back wheel: about $5.15\times10^3\,\text{N}$ .
  12. 12. (a) $5.0\times10^4\,\text{J}$ . (b) $6.6\times10^{-3}\,\text{kg}$ , about $6.6\,\text{g}$ of fat.
  13. 13. (a) Thermometer A: $392.7\,\text{K}$ ; thermometer B: $392.0\,\text{K}$ . (b) The gases are not perfectly ideal at finite pressure; reducing pressure and extrapolating to zero pressure reduces the discrepancy.
  14. 14. $l_x=yp_z-zp_y$ , $l_y=zp_x-xp_z$ , $l_z=xp_y-yp_x$ . If motion is confined to the $x-y$ plane, then $z=0$ and $p_z=0$ , so only $l_z$ remains.
  15. 15. The average density is about $1.4\times10^3\,\text{kg m}^{-3}$ , in the range of liquids/solids rather than ordinary gases.
  16. 16. $27\,\text{km h}^{-1}$ , unchanged.
  17. 17. $2.5\times10^3\,\text{K}$ approximately.
  18. 18. (a) $6.4\pi\,\text{rad}$ ; (b) $0.8\pi\,\text{rad}$ ; (c) $\pi\,\text{rad}$ ; (d) $3\pi/2\,\text{rad}$ .
  19. 19. For a uniform sphere, cylinder, ring and cube, the centre of mass is at the geometrical centre. The centre of mass need not necessarily lie inside the material of the body; for a ring it lies at the centre, where there is no material.
  20. 20. $94.1$ .
Brain Grain · braingrain.in
Physics — Practice Paper · Set 2
Class: 11CBSE / NCERTMax Marks: 34
Name: ____________________Reg No: ____________
Part I — Multiple Choice Questions 6 × 1 = 6

Choose the correct answer. (Answer all questions.)

1.In the following two exercises, choose the correct answer from among the given ones: The gravitational intensity at the centre of a hemispherical shell of uniform mass density has the direction indicated by the arrow (see Fig 7.11) (i) a, (ii) b, (iii) c, (iv) 0.i. aii. biii. civ. 0[1]
2.If, in Exercise 4.21, the speed of the stone is increased beyond the maximum permissible value, and the string breaks suddenly, which of the following correctly describes the trajectory of the stone after the string breaks :a. the stone moves radially outwardsb. the stone flies off tangentially from the instant the string breaksc. the stone flies off at an angle with the tangent whose magnitude depends on the speed of the particle ?[1]
3.A body is initially at rest. It undergoes one-dimensional motion with constant acceleration. The power delivered to it at time t is proportional toi. t^(1/2)ii. tiii. t^(3/2)iv. t^2[1]
4.One end of a string of length l is connected to a particle of mass m and the other to a small peg on a smooth horizontal table. If the particle moves in a circle with speed v the net force on the particle (directed towards the centre) is : T is the tension in the string. [Choose the correct alternative].i. Tii. T - mv^2/liii. T + mv^2/liv. 0[1]
5.A body is moving unidirectionally under the influence of a source of constant power. Its displacement in time t is proportional toi. t^(1/2)ii. tiii. t^(3/2)iv. t^2[1]
6.Two identical ball bearings in contact with each other and resting on a frictionless table are hit head-on by another ball bearing of the same mass moving initially with a speed V. If the collision is elastic, which of the following (Fig. 5.14) is a possible result after collision ?i. Ball 1 stops and balls 2 and 3 move together with speed V/2.ii. Balls 1 and 2 stop and ball 3 moves with speed V.iii. All three balls move together with speed V/3.[1]
Part II — Short Answer Questions 14 × 2 = 28

Answer briefly. (Answer all questions.)

7.A solid cylinder of mass 20 kg rotates about its axis with angular speed 100 rad s-1. The radius of the cylinder is 0.25 m. What is the kinetic energy associated with the rotation of the cylinder? What is the magnitude of angular momentum of the cylinder about its axis?[2]
8.You have learnt that a travelling wave in one dimension is represented by a function y = f (x, t) where x and t must appear in the combination x – v t or x + v t, i.e. y = f (x ± v t). Is the converse true? Examine if the following functions for y can possibly represent a travelling wave : (a) (x – vt )2 (b) log [(x + vt)/x0] (c) 1/(x + vt)[2]
9.A calorie is a unit of heat (energy in transit) and it equals about 4.2 J where 1J = 1 kg m2 s–2. Suppose we employ a system of units in which the unit of mass equals α kg, the unit of length equals β m, the unit of time is γ s. Show that a calorie has a magnitude 4.2 α –1 β –2 γ 2 in terms of the new units.[2]
10.Answer the following : (a) The casing of a rocket in flight burns up due to friction. At whose expense is the heat energy required for burning obtained? The rocket or the atmosphere? (b) Comets move around the sun in highly elliptical orbits. The gravitational force on the comet due to the sun is not normal to the comet’s velocity in general. Yet the work done by the gravitational force over every complete orbit of the comet is zero. Why ? (c) An artificial satellite orbiting the earth in very thin atmosphere loses its energy gradually due to dissipation against atmospheric resistance, however small. Why then does its speed increase progressively as it comes closer and closer to the earth ? (d) In Fig. 5.13(i) the man walks 2 m carrying a mass of 15 kg on his hands. In Fig. 5.13(ii), he walks the same distance pulling the rope behind him. The rope goes over a pulley, and a mass of 15 kg hangs at its other end. In which case is the work done greater ?[2]
11.A 14.5 kg mass, fastened to the end of a steel wire of unstretched length 1.0 m, is whirled in a vertical circle with an angular velocity of 2 rev/s at the bottom of the circle. The cross-sectional area of the wire is 0.065 cm2. Calculate the elongation of the wire when the mass is at the lowest point of its path.[2]
12.The escape speed of a projectile on the earth’s surface is 11.2 km s–1. A body is projected out with thrice this speed. What is the speed of the body far away from the earth? Ignore the presence of the sun and other planets.[2]
13.Read each statement below carefully and state, with reasons, if it is true or false : (a) The net acceleration of a particle in circular motion is always along the radius of the circle towards the centre (b) The velocity vector of a particle at a point is always along the tangent to the path of the particle at that point (c) The acceleration vector of a particle in uniform circular motion averaged over one cycle is a null vector[2]
14.The sign of work done by a force on a body is important to understand. State carefully if the following quantities are positive or negative: (a) work done by a man in lifting a bucket out of a well by means of a rope tied to the bucket. (b) work done by gravitational force in the above case, (c) work done by friction on a body sliding down an inclined plane, (d) work done by an applied force on a body moving on a rough horizontal plane with uniform velocity, (e) work done by the resistive force of air on a vibrating pendulum in bringing it to rest.[2]
15.State, for each of the following physical quantities, if it is a scalar or a vector : volume, mass, speed, acceleration, density, number of moles, velocity, angular frequency, displacement, angular velocity.[2]
16.Explain why (a) The blood pressure in humans is greater at the feet than at the brain (b) Atmospheric pressure at a height of about 6 km decreases to nearly half of its value at the sea level, though the height of the atmosphere is more than 100 km (c) Hydrostatic pressure is a scalar quantity even though pressure is force divided by area.[2]
17.A particle starts from the origin at t = 0 s with a velocity of 10.0 jɵ m/s and moves in the x-y plane with a constant acceleration of (8.0 iɵ + 2.0 jɵ) m s-2. (a) At what time is the x- coordinate of the particle 16 m? What is the y-coordinate of the particle at that time? (b) What is the speed of the particle at the time ?[2]
18.Two bodies of masses 10 kg and 20 kg respectively kept on a smooth, horizontal surface are tied to the ends of a light string. A horizontal force F = 600 N is applied to (i) A, (ii) B along the direction of string. What is the tension in the string in each case?[2]
19.Explain clearly, with examples, the distinction between : (a) magnitude of displacement (sometimes called distance) over an interval of time, and the total length of path covered by a particle over the same interval; (b) magnitude of average velocity over an interval of time, and the average speed over the same interval. [Average speed of a particle over an interval of time is defined as the total path length divided by the time interval]. Show in both (a) and (b) that the second quantity is either greater than or equal to the first. When is the equality sign true ? [For simplicity, consider one-dimensional motion only].[2]
20.An aircraft executes a horizontal loop of radius 1.00 km with a steady speed of 900 km/h. Compare its centripetal acceleration with the acceleration due to gravity.[2]
🔑 Show Answer Key — Set 2
  1. 1. (iii) c.
  2. 2. (b) the stone flies off tangentially from the instant the string breaks.
  3. 3. (ii) $t$ .
  4. 4. (i) $T$ .
  5. 5. (iii) $t^{3/2}$ .
  6. 6. (ii).
  7. 7. Rotational kinetic energy is $3.125\times10^3\,\text{J}$ . Angular momentum is $62.5\,\text{kg m}^2\text{s}^{-1}$ .
  8. 8. Yes. All three can represent travelling waves mathematically, subject to their domains.
  9. 9. $1\,\text{cal}=4.2\alpha^{-1}\beta^{-2}\gamma^2$ in the new unit of energy.
  10. 10. (a) At the expense of the rocket's mechanical energy. (b) Gravity is conservative, so work over a closed orbit is zero. (c) As orbital radius decreases, the satellite's potential energy decreases and its orbital speed increases despite loss of total mechanical energy. (d) Work is greater in Fig. 5.13(ii).
  11. 11. $1.9\times10^{-3}\,\text{m}$ approximately.
  12. 12. $31.7\,\text{km s}^{-1}$ .
  13. 13. a. False; b. True; c. True.
  14. 14. (a) Positive. (b) Negative. (c) Negative. (d) Positive. (e) Negative.
  15. 15. Scalars: volume, mass, speed, density, number of moles, angular frequency. Vectors: acceleration, velocity, displacement, angular velocity.
  16. 16. (a) Feet are at greater depth below the heart/brain, so hydrostatic pressure is larger. (b) Air density decreases rapidly with height, so much of the atmosphere's mass lies near the earth's surface. (c) Pressure at a point in a fluid has the same value in all directions; the force direction comes from the surface normal, not from pressure itself.
  17. 17. a. $t=2.0\,\text{s}$ and $y=24\,\text{m}$ ; b. speed $=21.3\,\text{m s}^{-1}$ .
  18. 18. If the 600 N force is applied to the 10 kg body A, $T=400\,\text{N}$ . If it is applied to the 20 kg body B, $T=200\,\text{N}$ .
  19. 19. Path length is always greater than or equal to magnitude of displacement. Average speed is always greater than or equal to magnitude of average velocity. Equality holds when motion is along one direction without reversal.
  20. 20. $a_c=62.5\,\text{m s}^{-2}\approx6.4g$ .
Brain Grain · braingrain.in
Physics — Practice Paper · Set 3
Class: 11CBSE / NCERTMax Marks: 34
Name: ____________________Reg No: ____________
Part I — Multiple Choice Questions 6 × 1 = 6

Choose the correct answer. (Answer all questions.)

1.One end of a string of length l is connected to a particle of mass m and the other to a small peg on a smooth horizontal table. If the particle moves in a circle with speed v the net force on the particle (directed towards the centre) is : T is the tension in the string. [Choose the correct alternative].i. Tii. T - mv^2/liii. T + mv^2/liv. 0[1]
2.A body is moving unidirectionally under the influence of a source of constant power. Its displacement in time t is proportional toi. t^(1/2)ii. tiii. t^(3/2)iv. t^2[1]
3.Two identical ball bearings in contact with each other and resting on a frictionless table are hit head-on by another ball bearing of the same mass moving initially with a speed V. If the collision is elastic, which of the following (Fig. 5.14) is a possible result after collision ?i. Ball 1 stops and balls 2 and 3 move together with speed V/2.ii. Balls 1 and 2 stop and ball 3 moves with speed V.iii. All three balls move together with speed V/3.[1]
4.In the following two exercises, choose the correct answer from among the given ones: The gravitational intensity at the centre of a hemispherical shell of uniform mass density has the direction indicated by the arrow (see Fig 7.11) (i) a, (ii) b, (iii) c, (iv) 0.i. aii. biii. civ. 0[1]
5.If, in Exercise 4.21, the speed of the stone is increased beyond the maximum permissible value, and the string breaks suddenly, which of the following correctly describes the trajectory of the stone after the string breaks :a. the stone moves radially outwardsb. the stone flies off tangentially from the instant the string breaksc. the stone flies off at an angle with the tangent whose magnitude depends on the speed of the particle ?[1]
6.A body is initially at rest. It undergoes one-dimensional motion with constant acceleration. The power delivered to it at time t is proportional toi. t^(1/2)ii. tiii. t^(3/2)iv. t^2[1]
Part II — Short Answer Questions 14 × 2 = 28

Answer briefly. (Answer all questions.)

7.Answer carefully, with reasons : (a) In an elastic collision of two billiard balls, is the total kinetic energy conserved during the short time of collision of the balls (i.e. when they are in contact) ? (b) Is the total linear momentum conserved during the short time of an elastic collision of two balls ? (c) What are the answers to (a) and (b) for an inelastic collision ? (d) If the potential energy of two billiard balls depends only on the separation distance between their centres, is the collision elastic or inelastic ? (Note, we are talking here of potential energy corresponding to the force during collision, not gravitational potential energy).[2]
8.A rocket with a lift-off mass 20,000 kg is blasted upwards with an initial acceleration of 5.0 m s-2. Calculate the initial thrust (force) of the blast.[2]
9.Underline the correct alternative : (a) When a conservative force does positive work on a body, the potential energy of the body increases/decreases/remains unaltered. (b) Work done by a body against friction always results in a loss of its kinetic/potential energy. (c) The rate of change of total momentum of a many-particle system is proportional to the external force/sum of the internal forces on the system. (d) In an inelastic collision of two bodies, the quantities which do not change after the collision are the total kinetic energy/total linear momentum/total energy of the system of two bodies.[2]
10.The oxygen molecule has a mass of 5.30 × 10-26 kg and a moment of inertia of 1.94 ×10-46 kg m2 about an axis through its centre perpendicular to the lines joining the two atoms. Suppose the mean speed of such a molecule in a gas is 500 m/s and that its kinetic energy of rotation is two thirds of its kinetic energy of translation. Find the average angular velocity of the molecule.[2]
11.Choose the correct alternative: (a) If the zero of potential energy is at infinity, the total energy of an orbiting satellite is negative of its kinetic/potential energy. (b) The energy required to launch an orbiting satellite out of earth’s gravitational influence is more/less than the energy required to project a stationary object at the same height (as the satellite) out of earth’s influence.[2]
12.Two masses 8 kg and 12 kg are connected at the two ends of a light inextensible string that goes over a frictionless pulley. Find the acceleration of the masses, and the tension in the string when the masses are released.[2]
13.Answer the following : (a) The triple-point of water is a standard fixed point in modern thermometry. Why ? What is wrong in taking the melting point of ice and the boiling point of water as standard fixed points (as was originally done in the Celsius scale) ? (b) There were two fixed points in the original Celsius scale as mentioned above which were assigned the number 0 °C and 100 °C respectively. On the absolute scale, one of the fixed points is the triple-point of water, which on the Kelvin absolute scale is assigned the number 273.16 K. What is the other fixed point on this (Kelvin) scale ? (c) The absolute temperature (Kelvin scale) T is related to the temperature tc on the Celsius scale by tc = T – 273.15 Why do we have 273.15 in this relation, and not 273.16 ? (d) What is the temperature of the triple-point of water on an absolute scale whose unit interval size is equal to that of the Fahrenheit scale ?[2]
14.Given below are some functions of x and t to represent the displacement (transverse or longitudinal) of an elastic wave. State which of these represent (i) a travelling wave, (ii) a stationary wave or (iii) none at all: (a) y = 2 cos (3x) sin (10t) (b) y = 2√(x – vt) (c) y = 3 sin (5x – 0.5t) + 4 cos (5x – 0.5t) (d) y = cos x sin t + cos 2x sin 2t[2]
15.The length, breadth and thickness of a rectangular sheet of metal are 4.234 m, 1.005 m, and 2.01 cm respectively. Give the area and volume of the sheet to correct significant figures.[2]
16.Which of the following functions of time represent (a) simple harmonic, (b) periodic but not simple harmonic, and (c) non-periodic motion? Give period for each case of periodic motion (ω is any positive constant): (a) sin ωt – cos ωt (b) sin3 ωt (c) 3 cos (π/4 – 2ωt) (d) cos ωt + cos 3ωt + cos 5ωt (e) exp (–ω2t2) (f) 1 + ωt + ω2t2[2]
17.A hydraulic automobile lift is designed to lift cars with a maximum mass of 3000 kg. The area of cross-section of the piston carrying the load is 425 cm2. What maximum pressure would the smaller piston have to bear ?[2]
18.A body of mass 2 kg initially at rest moves under the action of an applied horizontal force of 7 N on a table with coefficient of kinetic friction = 0.1. Compute the (a) work done by the applied force in 10 s, (b) work done by friction in 10 s, (c) work done by the net force on the body in 10 s, (d) change in kinetic energy of the body in 10 s, and interpret your results.[2]
19.An aircraft is flying at a height of 3400 m above the ground. If the angle subtended at a ground observation point by the aircraft positions 10.0 s a part is 30°, wat is the speed of the aircraft ?[2]
20.Determine the volume contraction of a solid copper cube, 10 cm on an edge, when subjected to a hydraulic pressure of 7.0 × 106 Pa.[2]
🔑 Show Answer Key — Set 3
  1. 1. (i) $T$ .
  2. 2. (iii) $t^{3/2}$ .
  3. 3. (ii).
  4. 4. (iii) c.
  5. 5. (b) the stone flies off tangentially from the instant the string breaks.
  6. 6. (ii) $t$ .
  7. 7. (a) No, not during contact. (b) Yes, if external forces are negligible. (c) For an inelastic collision, kinetic energy is not conserved, but linear momentum is conserved if external forces are negligible. (d) Elastic.
  8. 8. $3.0\times 10^5\,\text{N}$ upward.
  9. 9. (a) decreases. (b) kinetic. (c) external force. (d) total linear momentum and total energy; total kinetic energy does not remain unchanged.
  10. 10. $6.75\times10^{12}\,\text{rad s}^{-1}$ .
  11. 11. (a) negative of its kinetic energy. (b) less.
  12. 12. Acceleration is $2\,\text{m s}^{-2}$ , with the 12 kg mass moving downward and the 8 kg mass moving upward. Tension is $96\,\text{N}$ .
  13. 13. (a) The triple point is unique and reproducible; melting and boiling points depend on pressure and impurities. (b) Absolute zero, $0\,\text{K}$ . (c) The triple point of water is $0.01^\circ\text{C}$ , so $0^\circ\text{C}=273.15\,\text{K}$ . (d) $491.69$ on that absolute Fahrenheit-size scale.
  14. 14. (a) stationary wave; (b) travelling wave; (c) travelling wave; (d) none of these as a single travelling or stationary wave.
  15. 15. Area $=4.255\,\text{m}^2$ ; volume $=8.55\times10^{-2}\,\text{m}^3$ .
  16. 16. (a) SHM, period $2\pi/\omega$ ; (b) periodic but not SHM, period $2\pi/\omega$ ; (c) SHM, period $\pi/\omega$ ; (d) periodic but not SHM, period $2\pi/\omega$ ; (e) non-periodic; (f) non-periodic.
  17. 17. $6.9\times10^5\,\text{Pa}$ .
  18. 18. (a) $875\,\text{J}$ . (b) $-250\,\text{J}$ . (c) $625\,\text{J}$ . (d) $625\,\text{J}$ .
  19. 19. $1.82\times10^2\,\text{m s}^{-1}$ , approximately $656\,\text{km h}^{-1}$ .
  20. 20. $5.0\times10^{-8}\,\text{m}^3$ .

📄 About official papers

Class 11 does not have a public board examination, so there are no official board question papers for this class. The papers above are Brain Grain practice papers built to the standard exam pattern — ideal for unit tests, monthly tests and revision.

Practise more — your way

⚙️ Generate unlimited custom papers🎯 Practise MCQs & earn XP

Every paper above is generated from the same 23,000+ verified Brain Grain question bank.