The least velocity required to throw a body away from the surface of a planet so that it may not return is (radius of the planet is ( 6.4×106 m, g=9.8 m/sec2) (a) 9.8 ×10-3 m/sec …
Young’s modulus of rubber is 104 N/m2 and area of cross-section is 2 cm2 . If force of 2×105 dynes is applied along its length, then its initial length l becomes (a) 3L …
For silver, Young’s modulus is 7.25×1010 N/m2 and Bulk modulus is 11×1010 N/m. Its Poisson’s ratio will be (a) – 1 …
The length of a wire is 1.0 m and the area of cross-section is 1.0×10-2 cm2 . If the work done for increase in length by 0.2 cm is 0.4 joule, then Young’s modulus of the material of the wire …
46.A force of 200 N is applied at one end of a wire of length 2 m and having area of cross-section 10-2 cm2 . The other end of the wire is rigidly fixed. If coefficient of linear expansion of the …
A ball of radius 11 cm and mass 8 kg rolls from rest down a ramp of length 2m. The ramp is inclined at 35° to the horizontal. When the ball reaches the bottom, its velocity is (sin 35o = …
40. The interatomic distance for a metal is 3×10-10 m . If the interatomic force constant is 3.6×10–9 N/Å , then the Young’s modulus in N/m2 will be (a) 1.2×1011 …
Longitudinal stress of 1 kg/mm2 is applied on a wire. The percentage increase in length is (Y=1011 N/m2) (a) 0.002 (b) 0.001 (c) 0.003 …
How much energy will be necessary for making a body of 500 kg escape from the earth [g=9.8 m/s2 , radius of earth 6.4×106 m] (a) About 9.8×106 J (b) About 6.4×108 J (c) …
33. An aluminum rod (Young’s modulus=7×109 N/m2) has a breaking strain of 0.2%. The minimum cross-sectional area of the rod in order to support a load of 104 Newton’s is (a) 1×10-2 m2 …
A ring takes time t1 in slipping down an inclined plane of length L and takes time t2 in rolling down the same plane. The ratio t1/t2 is (a) √2:1 (b) 1:√2 (c) 1 : 2 (d) 2 : 1 Ans. …
A hollow cylinder is rolling on an inclined plane, inclined at an angle of 30° to the horizontal. Its speed after travelling a distance of 10 m will be (a) 49 m/sec (b) 0.7 m/sec (c) 7 m/sec (d) Zero …
v e and vp denotes the escape velocity from the earth and another planet having twice the radius and the same mean density as the earth. Then (a) ve = vp …
Solid cylinders of radii r1,r2,r3 and roll down an inclined plane from the same place simultaneously. If , r1>r2>r3 which one would reach the bottom first (a) Cylinder of radius (b) Cylinder of radius (c) Cylinder of radius (d) All …
An inclined plane makes an angle of 30° with the horizontal. A solid sphere rolling down this inclined plane from rest without slipping has a linear acceleration equal to (a) g/3 (b) 2g/3 (c) …
A body rotating at 20 rad/sec is acted upon by a constant torque providing it a deceleration of 2 rad/sec2. At what time will the body have kinetic energy same as the initial value if the torque continues to act …
32. A rod of length l and area of cross-section A is heated from 0°C to 100°C. The rod is so placed that it is not allowed to increase in length, then the force developed is proportional to (a) …
31.The temperature of a wire of length 1 metre and area of cross-section is 1 cm2 is increased from 0°C to 100°C. If the rod is not allowed to increase in length, the force required will be (α=10-5/°C and Y=1011 …
30. Increase in length of a wire is 1 mm when suspended by a weight. If the same weight is suspended on a wire of double its length and double its radius, the increase in length will (a) 2 mm …
29. An area of cross-section of rubber string is 2 cm2 . Its length is doubled when stretched with a linear force of 2×105dynes. The Young’s modulus of the rubber in dyne/cm2 will be (a) 4×105 …
28. Steel and copper wires of same length are stretched by the same weight one after the other. Young’s modulus of steel and copper are 2×1011 N/m2 and 1.2×1011 N/m2 . The ratio of increase in length (a) 2/5 …
27. Why the spring is made up of steel in comparison of copper (a) Copper is more costly than steel (b) Copper is more elastic than steel (c) Steel is more elastic than copper (d) None of the above ANSWER-C …
26.Two wires of equal lengths are made of the same material. Wire A has a diameter that is twice as that of wire B. If identical weights are suspended from the ends of these wires, the increase in length is …
25. The spring balance does not read properly after its long use, because (a) The elasticity of spring increases (b) The elasticity decreases (c) Its plastic power decreases (d) Its plastic power increases EXPLANATION-B (243)
A flywheel has moment of inertia 4 kg-m2 and has kinetic energy of 200 J. Calculate the number of revolutions it makes before coming to rest if a constant opposing couple of 5N-m is applied to the flywheel (a) 12.8 …
A wheel of moment of inertia 10 kg-m2 is rotating at 10 rotations per minute. The work done in increasing its speed to 5 times its initial value, will be (a) 100 J (b) 131.4 J (c) 13.4 J (d) …
The Young’s modulus of a rubber string 8 cm long and density 1.5 kg/m3 is 5×108 N/m2 , is suspended on the ceiling in a room. The increase in length due to its own weight will be (a) 9.6×10-5 m …
(a) Laws of motion (b) Laws of rotational motion (c) Laws of planetory motion (d) Laws of curvilinear motion Answer: c (6)
(a) Antheredium (b) Protonema (c) Archegonia (d) Capsule Ans. b (6)
(a) 1/2 year (b) 2√2 years (c) 4 years (d) 8 years Answer: b (4)
(a) Meroblastic (b) Coeloblastic (c) Metablastic (d) Holoblastic Ans. d (6)
(a) 1 : 2 (b) 1 : 1 (c) 1 : 3 (d) None of these Answer: b (5)
A satellite A of mass m is at a distance of r from the centre of the earth. Another satellite B of mass 2m is at a distance of 2r from the earth’s centre. Their time periods are in the …
(a) Antheridiophore (b) Archegoniophore (c) Sporophyte (d) Gametophyte Ans. c (8)
(a) Haploid (b) Tetraploid (c) Diploid (d) Triploid Ans. c (6)
(a) Conservation of energy (b) Conservation of linear momentum (c) Conservation of angular momentum (d) None of these Answer: c (6)
(a) Fertile tissue (b) Photosynthesis (c) Nutrition (d) Protecting tissue Ans. c (7)
(a) 8 times (b) 4 times (c) 1/8 times (d) 1/4 times Answer: c (22)
(a) Xylem (b) Phloem (c) Pith (d) Conducting tissue Ans. d (58)