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I-Term Exams-2021, Subject : PHYSICS, Class -11th (Objective), , Time :- 1½ Hours, , MM-35, , General Instructions:, 1. The Question Paper contains three sections., 2. Section A has 25 questions. Attempt any 20 questions., 3. Section B has 24 questions. Attempt any 20 questions., 4. Section C has 6 questions. Attempt any 5 questions., 5. There is no negative marking., 6. MCQ carry equal marks., , Section-A, 1., , Which is self adjusting force, (a) Static friction, , 2., , 3., , 5., , (b) Newton’s second law of motion, , (c) Newton’s third law of motion, , (d) None of the above, , The relation between coefficient of friction and the angle of friction is, (b)   cos , , (c)   tan , , (a) [ML2T-2], [ML2T-2], [ML2T-3], , (b) [ML2T-2], [ML2T-2], [ML2T-2], , (c) [ML2T-3], [ML2T-2], [ML2T-2], , (d) [ML2T-3], [ML2T-3], [ML2T-2], , During inelastic collision between two bodies, which of the following quantities always remain conserved ?, (b) Total linear momentum, (d) None of these, , Which of the followings is not the unit of energy ?, (a) Kilowatt, , (b) Calorie, , (c) Electron - volt, , (d) Joule, , For perfectly elastic and perfectly inelastic collision, the value of coefficient of restitution are respectively, (a) 1, 0, , 8, , (d)   tan , , Dimension of work, energy and power are respectively, , (c) Speed of each body, , 7., , (d) None of these, , (a) Newton’s first law of motion, , (a) Total kinetic energy, 6., , (c) Both (a) and (b), , Swimming is explained by, , (a)   sin , 4., , (b) Kinetic friction, , (b) 0, 1, , (c) +1, -1, , (d) 0, -1, , Can centre of mass be outside a physical body ?, (a) No, (b) Yes, if the body has uniform density, (c) Yes, if the shape of the body is open type, (d) Yes, if centre of mass and centre of gravity do not coincide, , 9., , Which of the following statements is true regarding vector product and scalar product of two vectors?, (a) scalar product of two vectors is commutative but the vector product of two vectors is not commutative, (b) Both scalar and vector product are commutative

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(c) Both scalar and vector product are not commutative., (d) vector product of two vectors is commutative but the scalar product of two vectors is not commutative, 10., , One quarter sector is cut from a uniform circular disc of radius R. This sector has a mass M. It is, made to rotate about a line perpendicular to its plane and passing through the centre of the disc. Its, moment of inertia about the axis of rotation is, (a), , 11., , L, 12, , 1 2, mv, 2, , (b), , 17., , 18., , Resistance R , , 23., , (c), , 1 2, Iv, 2, , (d), , 1 2, I, 2, , (c) 11.2 m/s, , (d) 112 m/s, , (c) 85 days, , (d) 85 seconds, , (b) 2%, , (c) 10%, , (d) 7%, , Average density of earth, (a) Does not depend on g, , (b) Is a complex function of g, , (c) Directly proportional to g, , (d) Inversely propotional to g, , Motion in straight line is called, (a) Rectilinear motion, , (b) Curvilinear motion, , (c) Two dimensional motion, , (d) None of these, , When 5.225 and 5.235 are rounded off to three significant figures they become, (b) 5.23, 5.24, , (c) 5.22, 5.23, , (d) 5.23, 5.23, , Two trains, each 100 m long are travelling in opposite direction with velocity 10 m/s and 15 m/s. The time of, crossing is, (b) 40 s, , (c) 8 s, , (d) 1.6 s, , A body is thrown straight up. Its velocity and acceleration at the top most position is, (b) 0, g, , (c) 0, -g, , (d) Vmax’g, , The angle between vectors 4i + 3j - 4k and 3i + 4j + 6k is, (a) 90°, , 22., , 1, m 2, 2, , V, . If V  (100  5)V and I  (10  0.2) A . The percentage error in the value of R is, I, , (a) 0, 0, 21., , (d) 12L2, , (b) 85 hours, , (a) 20 s, 20., , L2, 12, , For a satellite very close to the surface of earth the time period is, , (a) 5.22, 5.24, 19., , (c), , (b) 11.2 km/s, , (a) 5%, 16., , (d) 4MR 2, , Escape velocity at earth is, , (a) 85 minutes, 15., , (c) 2MR 2, , 12, L, , (b), , (a) 1.12 km/s, 14., , 1, MR 2, 2, , Energy stored in flywheel is, (a), , 13., , (b), , The radius of gyration of a thin rod of length L, about the perpendicular axis at its midpoint is, (a), , 12., , 1, MR 2, 4, , (b) 45°, , (c) 60°, , (d) 0°, , Null vector has, (a) Magnitude zero, , (b) Direction arbitrary, , (c) Both (a) and (b), , (d) None of the these, , `Which of the following is not correct ?, (a) A  B  B  A, , (b) A.B  B. A, , (c) A  B  B  A, , (d) None of these

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24., , What type of energy is stored in the spring while winding it?, (a) Kinetic, , 25., , (b) Potential, , (c) Both (a) and (b), , (d) None of these, , A fizzy drink beverage bottle is kept on a balance and the cap is opened. Will thre be any change in, the balance ?, (a) There will be no change, , (b) Weight will increase, , (c) Weight will decrease, , (d) Weight will initially increase and then decrease, , Section-B, 26., , A 2 kg stone ties at the end of a string 2 m long is whirled in a vertical circle at a constant speed of, 4 m/s. The tension in the string at the lowest point of the circle is, (a) 4N, , 27., , (c) 20N, , (d) 16N, , A player catches a cricket ball of mass 150 g moving at a rate of 20 m/s. If the catching process is, completed in 0.1 second the force exerted by the ball on the hand of the player is, (a) 300 N, , 28., , (b) 36N, , (b) 30 N, , (c) 3000 N, , (d) 705 N, , No work is done when, (a) The displacement is zero, (b) The force is zero, (c) The force and displacement are mutually perpendicular, (d) All of the above, , 29., , Which is the gain in potential energy of an object of mass m raised from the surface of earth to a, height R? (Acceleration due to gravity at the surface of earth = g, radius of earth = R), (a), , 1, mgR, 2, , (b) mgR, , (c) 2 mgR, , (d), , 1, mgR, 4, , 30., , 32., , An object moves under the effect of a force F = ax2, from x = 0 to x = x1. The work done in the, process is, (a), , 33., , 1 3, ax1, 3, , 1 2, ax1, 2, , (c) 3ax13, , (d) 2ax12, , (c) 346, , (d) 846, , 1 H.P. = ..............W, (a) 646, , 34., , (b), , (b) 746, , Why the diver stretches her arm and leg while touching the water ?, (a) to increase her moment of inertia, , (b) to decrease her moment of inertia, , (c) to relax her body, , (d) to increase her velocity

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35., , 36., , If torque is applied on a rotating body, (a) Its moment of inertia changes, , (b) Its angular velocity changes, , (c) Its angular velocity remains unchanged, , (d) Both (a) and (b), , The quantities which have the same dimensions are:, (a) stress and strain, , (b) stress and force, , (c) surface energy and surface tenstion (d) strain and work, 37., , The least count of the instrument when 1 MSD= 0.1 cm and number of vernier scale divisions = 10 is, (a) 0.1 cm, , 38., , (c) 0.001 cm, , (d) none of these, , In an experiment, four quantities a, b, c and d are measured with percentage errors 1%, 2%, 3% and, 4% respectively. Quantity P is calculated as P = a3b2 / cd.% error in P is :, (a) 14%, , 39., , (b) 0.01 cm, , (b) 10%, , (c) 7%, , (d) 4%, , A ball is travelling with uniform translatory motion. It means that, (a) It is at rest., (b) The path can be a straight line or circular and the ball travels with uniform speed, (c) All parts of the ball have the same velocity (magnitude and direction) and the velocity is constant., (d) The centre of the ball moves with constant velocity and the ball spins about its centre uniformly., , 40., , Banking of road at turnings is required, (a) To reduce the friction betweeen road and a tyre, (b) to provide the necessary centripetal force at the curved road, (c) to avoid the chance of skid, (d) Both (b) and (c), , 41., , Which one of the following statements is true ?, (a) Impending motion is the motion that would take place ( but does not actually take place ) under, the applied force, if friction is absent, (b) When there is no applied force, there is no static friction, (c) When two bodies are in contact, each experiences a contact force by the other, (d) All of the above., Directions: In the following questions, A statement of Assertion (A) is followed by a statement of, Reason (R). Mark the correct choice as, (a) Both A and R are true and R is the correct explanation of A, (b) Both A and R are true but R is NOT the correct explanation of A, (c) A is true but R is false, (d) A is false and R is True, , 42., , Assertion (A): If the magnitude of a physical quantity is 0, then it cannot be a vector., Reason (R): A vector quantity has both magnitude and direction., , 43., , Assertion (A): Work done over a closed path is always zero., Reason (R): No force is required in a closed path., , 44., , Assertion (A): Two bodies move to each other due to mutual attraction which causes the centre of, mass of the system to move., Reason (R): External forces causes the motion of the centre of mass., , 45., , Assertion (A) : Escape velocity is independent for angle of projection., Reason (R) : Escape velocity = 2gR

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46., , Assertion (A): Gravitational force of earth is much greater than that of moon., Reason (R): Mass of earth is much greater than that of moon, , 47., , Two bodies of masses m1 and m2 have equal K.E. What is the ratio of their linear momenta ?, m1, (a) m, 2, , 48., are :, , (c), , m2, m1, , (d), , m1, m2, , A body moves along a quadrant of a circle of radius r. The displacement and the distance travelled, (a) r 2, r / 2, , 49., , m2, (b) m, 1, , (b) r ,  r, , (c) 2 2 r ,  r, , (d) r,  r/ 2, , On a stationary sail boat, air is blown at the sails from a fan attached to the boat. The boat will :, (a) move forward, , (b) move backward, , (c) spin around (d) remain stationary, , Section-C, Read the following text and answer the following questions on the basis of the same:, Two friends started for a picnic spot, in two different cars. A drove his car at a constant velocity 60km/h., B drove his car at a constant velocity 50 km/h. The velocity of B relative to A is VB – VA, Similarly, the velocity of object A relative to object B is VA – VB Their friend C was supposed to wait, at a point on the road for a lift. Both of them forgot to pick up C. A and B reached the picnic spot, within 2 hours and 2 hours 24 minutes respectively. (Q. 50 to Q.53), 50., , What was the velocity of B relative to A?, (a) 10 km/h, , 51., , (c) 55 km/h, , (d) - 55 km/h, , (c) 55 km/h, , (d)-55 km/h, , What was the velocity of A relative to B?, (a) 10 km/h, , 52., , (b) -10 km/h, (b) -10 km/h, , What were the velocities of A and B relative to C?, (a) 50 km/h, 60 km/h, , (b) 60 km/h, 50 km/h, , (c) Both 10 km/h, , (d) Both 55 km/h, , 53., , Which one of the following shows of the Velocity - Time graph plot for A ?, , 54., , A pump ejects 12000 kg of water at speed of 4 m/s in 40 second. Find the average rate at which the, pump is working, (A) 0.24 KW, , 55., , (B) 2.4 W, , (C) 2.4 KW, , (D) 24 W, , A body of mass M hits normally a rigid wall with velocity v and bounces back with the same velocity. The, impulse experienced by the body is :, (a) Mv, , (b) 1.5 Mv, , (c) 2 Mv, , (d) zero