| PHYSICS and CHEMISTRY Answer Key |
1. If the wavelength of sound wave increases the pitch of sound
Ans.: (A) Decreases | 2. A metallic wire of specific resistance s is stretched in such a way that its length is doubled and area of cross section is halved. Then the specific resistance of the wire will be
Ans.:(B) s/2 |
3. If a glass prism is placed inside water then its dispersive power
(B) Decreases | 4. In case of vibration the restoring force is
Ans.:(A) proportional to displacement |
5. A current is passed through a conducting spring. Then the spring
Ans.:(D) remain unchanged | 6. The ratio of the masses of two body P and Q is 1:8 and the ratio of the kinetic energy is 2:1, then the ratio of their momentum is
Ans.: (C) 4:1 |
7. A space-craft of mass M moving with velocity v in space explodes and reaks into pieces. After the explosion a mass m of the space-craft is left statiobnary. The velocity of the other part is
Ans.: (B) Mv/(M-m) | 8. The resultant of two vectors of magnitudes 3 unit and 4 unit is 5 unit. The angel between the two vectors is
Ans.: (A) π/2 |
9. If the weight of a body is 9.8 kg then the mass of the body is
Ans.: (C) 9.8 kg | 10. The dimension of specific gravity is
(A)M0L0T0 |
11. A body of mass 10kg is falling vertically with uniform velocity. What is the resisting force of air?
Ans.: (C) 10 kg-wt | 12. If the electronic charge is 1.6 x 10-19 C, then the number of electrons passing through a section of wire per second, when the wire carries a current 2A, is
Ans.: (A) 1.25 x1017 |
13. The kinetic energy of a body of mass m is E. The momentum of the body is
Ans.: (B) √(2mE) | 14. Image formed by a plane mirror is always
Ans.:(C) virtual and of same size |
15. The minimum distance between the source and the reflector, so that an echo is heard is approximately equ; to (velocity of sound in air 332 m/s)
Ans.: (B) 16.6 m | 16. A constant force acts on two particles of masses 4kg and 16 kg during which both of them travel a dsitance of s meter. Both particles were initially at rest and they started off at the same time. The ratios of the speeds attained by them is
Ans.: (C) 2:1 |
17. If the acceleration due to gravity g, is about 10 m/s2 near the surface of the earth, then at the center of the earth g would have an approximate value of
Ans.: (A) Zero | 18. In case of an prism, the angel of deviation is greater for
Ans.: (A) violet |
19. Two resistances are joind in parallel whose resultant is 6/5 Ω. One of the resistance wires is broken and the effective resistance becomes 2 Ω. The resistance in ohm of the wire that got broken is
Ans.: (B) 3 Ω | 20. The molar gas constant is the same for all gases because, at the same pressur and temperature, equal volumes of all gass have the same
Ans.: (C) number of molecules |
21. If the object is placed at 2f from a convex lens, then
Ans.: (A) a real image is formed at 2f on the other side | 22. Which one of the following instrument can be regard as non-ohmic resistance
Ans.: (C) diode valve |
23. Among the moving particles (α, β, γ particle), which one or which ones are not deflected by the magnetic field?
Ans.: (D) γ particle | 24. An object is placed infornt of two plane mirrors which are perpendicular to each other. The number of images that can be seen by an observer is
Ans.: (D) Infinite |
25. 540 gm of ice at 0°C mixed with 540 gm of water at 80°C. The final temperature of the mixer is
Ans.: (B) 40°C | 26. Three resistance each of 4 ohm are connected to form an equilateral triangle. The equivalent resistance between any two corner is
Ans.: (D) 8/3 ohm |
27. 92U235, 92U238 differ as
(C)92U235 has three neutrons less | 28. Two bulbs when connected in parallel to a source, take 60 W each, The total power consumed when they are connected in series with the same source is
Ans.: (C) 60 W |
29. A train moving with a speed of 36 km/hr takes 14 sec to cross a bridge of length 100m. The length of the train is
Ans.: (B) 60 m | 30. The rate of radioactive disintegration increases
Ans.: (A) with the increase of temperature |
31. When a person uses a convex lens as a simple magnifying glass, the object must be placed at a distance
Ans.:(A) less than the focal length | 32. The end product of radioactive decays is
Ans.: (B) lead |
33. When a vapor condenses into liquid
Ans.:(B) it rejects heat | 34. One surface of a lens is convex and the other is concave. If radii of curvature are r1 and r2 respectively, then the lens will be convex if
Ans.: (C) r1<r2 |
35. An object is placed at a distance of f/2 from a convex lens of focal length f. The image will be
Ans.: (C) at 2f, vertual and erect | 36. A motor cycle and a car are moving on a horizontal road with same velocity. If they are brought to rest by the application of brakes, which provided equal retardation, then
Ans.: (C) both will stop at a same distance |
37. Choose the correct sequence of substance which is ordered in an increasing order of forces of attraction between the particles
ans.:(D) Oxygen, Water, Sugar | 38.In a Tsunami, the entire ocean, form the surface to the bottom, participate in the wave motion. For such waves, the wave speed is given by v=√(gh) where g is the acceleration due to gravity and h=3.0 Km is the depth of the ocean surface. A Tsunami has been detected at a point 250 Km from the shore. How much time would it take to reach the shore
Ans.:(C) 24 Minutes |
39. A thin wire of resistance 4 Ω is bent to form a circle. The resistance across any diameter is
Ans.: (C) 1 Ω | 40. The note middle C played om a piano differs from middle C played on a violin because of a difference in
Ans.: (D) harmonics |
41. A batch of five resistors have the same value. The Ratio of the maximum and the minimum resistance that can be made out of them
Ans.: (D) 25:1 | 42. Which device would most likely be classified as a load in an electrical circuit?
Ans.: (B) Light bulb |
43. At what common temperature a wooden block and a metallic block would be felt equally cold or equally hot when touched?
Ans.: (C) If the temperature of both the blocks equal the temperature of the person touching them | 44. The densities of two substances are the ratio 2:3 and their specific heats are in the ratio 4:3. Their thermal capacities per unit volume are in the ratio
Ans.: (C) 8:9 |
45. The freezing point on a thermometer is marked 30° and the boiling point is marked as 180°. The reading of the thermometer at 50°C is
Ans.:(C)105° | 46. In a nuclear reactor for control rod we use
Ans.: (D) Cadmium |
47. At STP amoung 32 gm of SO2,22 gm of CO2 and 17 gm of H2O gas
Ans.: (C) SAll gases have equal number of molecules | 48. Ideal gas equation for 1 mole of ideal gas is PV=RT, the SI unit of universal gas constant R is
Ans.: (C) J Kg-1K-1 |
49. Two plane mirrors are inclined to each other at an angle θ. A ray of light is reflected first at one mirror and then at the other. The total deviation of the ray is
Ans.: (A) 2θ | 50. Two resistance 1 Ω and 3 Ω are connected parallel and the combination is connected to a 2 volt source. The ratio of electric current through the resistance will be
Ans.: (B) 3:1n
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