Wednesday, April 24, 2019

WBCS Polity and Constitution MCQs Prelims and Mains

Physics MCQs of WBCS Prelims Previous Years Questions P16

151. The Earth's magnetic field
(A) is centered exactly at the Earth's center.
(B) originates in a permanently magnetized iron core.
(C) never change
(D) has reversed itself many times.

Correct Answer: [D] has reversed itself many times.

152. Graphite is used in a nuclear reactor
(A) For lining inside the reactor as an insulator.
(B) For reducing the velocity of the neutron.
(C) As a lubricant.
(D) As a fuel

Correct Answer: [B] For reducing the velocity of the neutron.

153. Which of the following is a good nuclear fuel?
(A) Neptunium 239
(B) Thorium 236
(C) Uranium 238
(D) Plutonium 239.

Correct Answer: [D] Plutonium 239.

154. A radioactive isotope has a half-life period of 3 days. After how many days I gm of it will change to 0.125 gm?
(A) 6 days
(B) 12 day
(C) 24 days
(D) 9 days.

Correct Answer: [D] 9 days.

155. Which of the following waves is used for telecommunication?
(A) Microwaves
(B) X-rays
(C) Infrared rays
(D) Ultraviolet rays.

Correct Answer: [A] Microwaves.

156. Which of the following is not a conservative force?
(A) Electrostatic force.
(B) Magnetostatic force.
(C) Gravitational force.
(D) Frictional force.

Correct Answer: [D] Frictional force.

157. The reverberation of sound in a half is due to continued
(A) diffraction
(B) absorption
(C) reflection
(D) interference.

Correct Answer: [D] interference.

158. Glass is best described as
(A) A eutectic mixture
(B) A supercooled solution
(C) A gel
(D) An alloy.

Correct Answer: [B] A supercooled solution.


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