Thursday, February 27, 2020

WBCS Polity and Constitution MCQs Prelims and Mains

general Physics test questions and answers For UPSC | SSC | Rail | RRB | State PSC P31

Physics - 31

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.


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