PHYSICS-24-12- 11th (J-Batch)

REVIEW TEST-6 Class : XI (J-Batch) Time : 2 hour Max. Marks : 130 INSTRUCTIONS 1. The question paper contains 13 pages and 3-parts. Part-A contains 20 objective questions, Part-B contains 3 "Match the Column" questions and Part-C contains 4 "Subjective" questions. All questions are compulsory. Please ensure that the Question Paper you have received contains all the QUESTIONS and Pages. If you found some mistake like missing questions or pages then contact immediately to the Invigilator. PART-A (i) Q.1 to Q.15 have only one correct alternative and carry 3 marks each. There is NEGATIVE marking and 1 mark will be deducted for each wrong answer. (ii) Q.16 to Q.20 have one or more than one correct alternative(s) and carry 5 marks each. There is NO NEGATIVE marking. Marks will be awarded only if all the correct alternatives are selected. PART-B (iii) Q.1 to Q.3 are "Match the Column" type which may have one or more than one matching options and carry 8 marks for each question. 2 marks will be awarded for each correct match within a question. There is NEGATIVE marking. 0.5 Marks will be deducted for each wrong match. Marks will be awarded only if all the correct alternative(s) is/are selected. PART-C (iv) Q.1 to Q.4 are "Subjective" questions and carry 9 marks each. There is NO NEGATIVE marking. Marks will be awarded only if all the correct bubbles are filled in your OMR answer sheet. 2. Indicate the correct answer for each question by filling appropriate bubble in your OMR answer sheet. 3. Use only HB pencil for darkening the bubble. 4. Use of Calculator, Log Table, Slide Rule and Mobile is not allowed. PART-B For example if correct match for (A) is P, Q; for (B) is P, R; for (C) is P and for (D) is S then the correct method for filling the bubbles is P Q R S (A) (B) (C) (D) PART-C Ensure that all columns (4 before decimal and 2 after decimal) are filled. Answer having blank column will be treated as incorrect. Insert leading zero(s) if required after rounding the result to 2 decimal places. e.g. 86 should be filled as 0086.00 Useful data: g = 10m/s2, tan370 = 0.75 PART-A Select the correct alternative. (Only one is correct) [15 × 3 = 45] There is NEGATIVE marking and 1 mark will be deducted for each wrong answer. Q.1 The S–shaped uniform wire shown in figure has a mass M, and the radius of curvature of each half is R. The moment of inertia about an axis through A and perpendicular to the plane of the paper is: (A) 3 MR 2 4 (B) MR2 (C) 3 MR 2 2 (D) 2MR2 Q.2 Two rods OA and OB of equal length and mass are lying in xy plane as shown in the figure. Let Ix, Iy and Iz be the moments of inertia of both the rods about x-, y- and z-axis, respectively, then (A) Ix = Iy > Iz (B) Ix = Iy < Iz (C) Iy < Ix < Iz (D) Iz > Iy > Ix Q.3 Figure shows a pair of pin jointed gripper tongs holding an object weighing 2000 N. The coefficient of friction  at the gripping surface is 0.1. X-X is the line of action of the input force and Y-Y is the line of application of normal gripping force. If the pin-joint is assumed as frictionless, the minimum magnitude of force F required to hold the weight is (A) 1000 N (B) 2000 N (C) 2500 N (D) 5000 N ROUGHWORK Q.4 A ring of mass M and radius R is at rest at the top of an incline as shown. The ring rolls down the plane without slipping. When the ring reaches bottom, its angular momentum about its center of mass is: (A) MR (B) MR (C) MR (D) none Q.5 A wheel of radius R = 0.1 m is rolling without slipping on a horizontal surface as shown in the figure. Centre of the wheel moves with a constant speed The speed of the point P with respect to ground is (A) 23 m/s (B) zero (C) 3 m/s (D) 3 m/s m/s. Q.6 Two bodies of mass 1 kg and 2 kg move towards each other in mutually perpendicular direction with the velocities 3 m/s and 2 m/s respectively. If the bodies stick together after collision the heat liberated will be (A)13 J (B) 13/3 J (C) 8 J (D) 7 J. Q.7 A ball is dropped on to a fixed horizontal surface from a height h, the coefficient of restitution is e. The average speed of the ball from the instant it is dropped till it goes to maximum height after first impact with ground (A) (1 + e) 2gh (1  e) (B) (C) (1  e2 ) 2gh (1 + e)2 (D) (1  e) 2gh (1 + e) ROUGHWORK Q.8 A T shaped object with dimensions shown in the figure is lying on a smooth floor. Aforce F is applied at the point P parallel to AB such that the object has only the translational motion without rotation. Find the location of P with respect to C. (A) (3/4)l (B) l (C) (4/3)l (D) (3/2)l Q.9 A steel wire, 3.2 m long, has a diameter of 1.2 mm. The wire stretches by 1.6 mm when it bears a load. Young's modulus for steel is 2.0 × 1011 Pa. The mass of the load is closest to: (A) 24 kg (B) 28 kg (C) 12 kg (D) 20 kg Q.10 A mass of 10 kg connected at the end of a rod of negligible mass is rotating in a circle of radius 30 cm with an angular velocity of 10 rad/s. If this mass is brought to rest in 10 s by a brake, what is the magnitude of the torque applied? (A) 0.9 Nm (B) 1.2 Nm (C) 2.3 Nm (D) 0.5 Nm Q.11 Two blocks of masses 20 kg and 50 kg are lying on a horizontal floor (coefficient of friction  = 0.5). Initially string is just taut and blocks are at rest. Now two forces 235 N and 150N is applied on two blocks as shown in figure. What is acceleration of 20 kg block (g = 10 m/s2) (A) 0.5 m/s2 (B) zero (C) 2.5 m/s2 (D) cannot be determined Q.12 A uniform sphere of weight W and radius 5 cm is being held by a string as shown in the figure. The wall is smooth . The tension in the string will be (A) 12 W / 5 (B) 13 W / 5 (C) 13 W / 12 (D) 12 W / 13 ROUGHWORK Q.13 A recording disc rotates steadily at n1 rps on a table. When a small mass m is dropped gently on the disc at a distance x from its axis, it sticks to the disc, the rate of revolution falls to n2 rps. The original moment of inertia of the disc about a perpendicular axis through its centre is mx2 n mx2 n mx2 n mx2 (A) I = n1  n2 (B) I = 1 n1  n2 (C) I = 2 n1  n2 (D) I = 2 n1 Q.14 A body undergoing SHM about the origin has its equation given by x = 0.2 cos 5t.[All units are in S.I.]. Find its average speed from t = 0 to t = 0.7 sec. (A) 1 (B) 2 (C) 4 (D) 3 Q.15 Potential Energy (U) of a body of unit mass moving in a one-dimensional conservative force field is given by, U = (x2 – 4x + 3). [All units are in S.I.]. The equilibrium position of the body is located at (A) x = 2m (B) x = 1m (C) x = 0 (D) none Select the correct alternatives. (one or more than one is/are correct) [5 × 5 = 25] There is NO NEGATIVE marking. Q.16 A disc of mass m and radius r is gently placed on another disc of mass 2m & radius r. The disc of mass 2m is rotating with angular velocity 0 initially. The disc is placed such that axis of both are coincident. The coefficient of friction is  for surfaces of contact. Assume that pressure on disc is uniformly distributed. Find the correct statement. 1 (A) Loss in kinetic energy of system K = 3 mr2 2 . 1 (B) Loss in kinetic energy of system K = 6 mr2 2 . ROUGHWORK (C) The common angular velocity is 2  . 3 0 4 (D) The common angular velocity is 3 0 Q.17 A spring block system is placed on a rough horizontal floor. The block is pulled towards right to give spring some elongation and released. (A) The block may stop before the spring attains its mean position. (B) The block must stop with spring having some compression. (C) The block may stop with spring having some compression. (D) It is not possible that the block stops at mean position. Q.18 A ball of mass 1 kg bounces against the smooth ground as shown in the figure. The approaching velocity is 25 m/s and the velocity after hitting the ground is 15 2 m/s. Select the correct alternative(s) (A) Magnitude of Impulse = 5 Ns (B) Magnitude of Impulse = 35 Ns (C) Cofficient of restitution, e = 0.75 (D) Cofficient of restitution, e = 0.25 Q.19 A thin bar of mass M and length L is free to rotate about a fixed horizontal axis through a point at its end. The bar is brought to a horizontal position and then released. The angular velocity when it reaches the lowest point is (A) directly proportional to its length and inversely proportional to its mass (B) independent of mass and inversely proportional to the square root of its length (C) dependent only upon the acceleration due to gravity and the length of the bar (D) directly proportional to its length and inversely proportional to the acceleration due to gravity ROUGHWORK Q.20 Particle having a velocity v = v0 at t = 0 is decelerated at the rate |a| =  , where  is a positive constant. (A) The particle comes to rest at t =  (B) The particle will come to rest at infinity. (C) The distance travelled by the particle is 2v3 / 2  . 2 v3 / 2 (D) The distance travelled by the particle is 0 . 3  ROUGHWORK PART-B MATCH THE COLUMN [3 × 8 = 24] There is NEGATIVE marking. 0.5 Marks will be deducted for each wrong match. INSTRUCTIONS: Column-I and column-II contains four entries each. Entries of column-I are to be matched with some entries of column-II. One or more than one entries of column-I mayhave the matching with the same entries of column-II and one entryof column-I mayhave one or more than one matching with entries of column-II. Q.1 Match the physical situation of Column I with the graph of Column II. The graphs depict the variation of total energy (solid), potential energy (long dashes) and kinetic energy (short dashes) with time. Column I Column II (A) A mass on a spring released from compression (P) until it reaches its maximum extension (B) An object in circular orbit around the sun (Q) (C) An object undergoing free fall (R) (D) An object being pulled on a level, frictionless (S) surface by a constant force in the horizontal direction ROUGHWORK Q.2 Atruck of mass M crashes into a tempo of mass m < M and the two masses stick together. For each pair of quantities below, state the relationship Column I Column II (A) (B) (C) (D) Quantity 1 Magnitude of force exerted by truck on tempo Magnitude of a cceleration of truck during collision Total kinetic energy of the 2 - vehicle system before collision Kinetic energy of the tempo before collision Quantity 2 Magnitude of force exerted by tempo on truck Magnitude of acceleration of tempoduring collision Total kinetic energy of the 2 - vehicle system after collision Kinetic energy of the tempo after collision (P) (Q) (R) (S) Quantity 1 > Quantity 2 Quantity 1 < Quantity 2 Quantity 1 = Quantity 2 Impossible to determine from information given Q.3 Aboat is being rowed in a river. Air is also blowing. Direction of velocity vectors of boat, water and air in ground frame are as shown in diagram. Column I Column II (Possible directions) (A) Direction in which boat is being steered (P) (B) Direction in which a flag on the (Q) boat may flutter (C) Direction of velocity of water (R) relative to boat (D) Direction of velocity of air relative (S) to a piece of wood floating on river ROUGHWORK PART-C SUBJECTIVE: [4 × 9 = 36] There is NO NEGATIVE marking. Q.1 An isosceles prism of mass 2 kg rests on a rough horizontal surface with coefficient of friction  = 0.8. Sides of triangular cross -section of prism are 10 cm, 10 cm and 12 cm as shown. A horizontal force F is applied on the prism as shown in the figure . Find maximum magnitude of F (in newton) for which the prism stays inequilibrium. Q.2 A ball of mass 1 kg moving with speed of 10 m/s on a smooth horizontal plane collides obliquely with another ball of same mass at rest as shown in the figure. If coefficient of restitution for the collision is 0.5, What will be the speed of the striking ball after the collision. Q.3 An annular wheel (M.I. = 32 kgm2) hinged at its centre is rotating with initial angular velocity 10 rad/s in anticlockwise direction. If the inner radius is 5 cm, the outer radius is 20 cm and the wheel is acted upon by the constant forces shown in the figure, then what will be the angular velocity of the wheel after 10 sec. (Assume that the lever arm of all forces about centre remains constant) Q.4 Two blocks of equal mass 2 kg are placed on a rough horizontal surface as shown and a force Fis applied on the upper block. The system is initially at rest. Find acceleartion of the lower block in m/s2.