## Wednesday, April 24, 2019 # General Science Previous Years Question of WBCS Prelims P5

41. The magnetic length of a bar magnet means
(A) It's width
(B) Its total length
(C) The distance of a pole from the center
(D) The distance between its two poles.
Correct Answer: [D] The distance between its two poles..

42. A shaving brush is dipped in water. When taken out the hairs of the brush are seen to be drawn together due to
(A) the elasticity of the hairs of the brush.
(B) the temperature difference between air and water.
(C) the surface tension of water.
(D) the viscosity of water.
Correct Answer: [C] the surface tension of water..

43. The viscosity of a liquid
(A) Independent of temperature.
(B) Decreases with increase in pressure.
(C) Increases with increase in temperature.
(D) Decreases with increase in temperature.
Correct Answer: [D] Decreases with increase in temperature..

44. How many times will the equivalent resistance of n identical conductors be changed if their parallel arrangement is changed into a series one
(A) n
(B) n2
(C) n3
(D) n4

45. The relative humidity inside a room is 50% while the temperature is 30°C. If the temperature becomes 40°C, then the relative humidity
(A) Will remain unchanged
(B) Will decrease
(C) Will increase
(D) Will increase or decrease depending upon the size of the room.

46. Dyne sec. stands for the unit of
(A) Energy
(B) Power
(C) Force
(D) Momentum.

47. Einstein was awarded the Nobel Prize for
(A) General theory of relativity
(B) Explanation of Brownian motion
(C) Photoelectric emission
(D) Special theory relativity.

48. The periodic time of a Pendulum depends on
(A) The shape of its Bob
(B) The volume of its Bob
(C) The density of its Bob
(D) Its length.

49. A piece of stone tied to a string is being rotated in a vertical plane with constant angular velocity. The tension of the string will be maximum when
(A) The string is horizontal
(B) The tension is always the same
(C) The stone is in the highest position
(D) The stone is in the lowest position.
Correct Answer: [D] The stone is in the lowest position..

50. The temperature at which Celsius and Fahrenheit's scales give the same reading is
(A) - 40°C
(B) 40°C
(C) 0°C
(D) 32°C.