WBCS Prelim 2019 Mental Ability and General Science P4

General Mental Ability and General Science

76. An arc of length 121 cm makes an angle 77° at the center of a circle. The radius of the circle is

(A) 110 cm

(B) 100 cm

(C) 90 cm

(D) 70 cm

Correct Answer: [C] 90 cm

77. The arithmetic mean of the numbers 9, 12, 15, 18, 20, 22 is increased by 1, if 15 is replaced by

(A) 16

(B) 17

(C) 19

(D) 21

Correct Answer: [D] 21

78. The number of spinal nerves in the human body is

(A) 12 pairs

(B) 31 pairs

(C) 31

(D) 12

Correct Answer: [B] 31 pairs

79. A bomb is dropped at a point from a moving airplane. The pilot observes that

(A) the bomb traverses a curved path and falls some distance behind that point.

(B) the bomb traverses a curved path and falls some distance ahead.

(C) the bomb drops vertically downward.

(D) the bomb remains stationary in the air for some time.

Correct Answer: [C] the bomb drops vertically downward.

80. Which of the following is used in beauty parlors for hair setting?

(A) Chlorine

(B) Sulphur

(C) Phosphorus

(D) Silicon

Correct Answer: [B] Sulphur

81. Which of the following fertilizers has more nitrogen content?

(A) Urea

(B) Ammonium Nitrate

(C) Potassium Nitrate

(D) Ammonium Phosphate

Correct Answer: [A] Urea

82. Good absorbers of heat are

(A) poor emitters

(B) non-emitters

(C) good emitters

(D) highly polished

Correct Answer: [C] good emitters

83. Ventilators are provided at the top of the room its

(A) to bring oxygen for breathing.

(B) so that sunlight may enter the room.

(C) to maintain convectional currents to keep the air fresh in the room.

(D) to provide an outlet for carbon dioxide.

Correct Answer: [C] to maintain convectional currents to keep the air fresh in the room.

84. Voice of your friend can be recognized by

(A) pitch

(B) quality

(C) intensity

(D) velocity

Correct Answer: [B] quality

85. Light year is

(A) the light emitted by the sun in one year.

(B) time taken by light to travel from Sun to Earth.

(C) the distance traveled by light in free space in one year.

(D) time is taken by earth to go once around the Sun.

Correct Answer: [C] the distance traveled by light in free space in one year.

86. Twinkling of stars is on account of

(A) large distance of stars and storms in air.

(B) rotation of the earth.

(C) the large size of stars.

(D) large distance of stars and fluctuations in the density of air.

Correct Answer: [D] large distance of stars and fluctuations in the density of air.

87. Select the one having pH < 7.

(A) Lemon juice

(B) Lime water

(C) Human blood

(D) Antacid

Correct Answer: [A] Lemon juice

88. To protect tooth decay we are advised to brush our teeth regularly. The nature of the toothpaste commonly used is

(A) acidic

(B) neutral

(C) basic

(D) corrosive

Correct Answer: [C] basic

89. Which one among the following is the main ingredient in cement?

(A) Gypsum

(B) Limestone

(C) Clay

(D) Ash

Correct Answer: [B] Limestone

90. Brass is a mixture of

(A) Copper & Zinc

(B) Copper & Tin

(C) Copper, Nickel & Zinc

(D) Copper, Aluminium & Mg

Correct Answer: [A] Copper & Zinc

91. The percentage increase in the surface area of a cube when each side doubled is

(A) 25%

(B) 50%

(C) 150%

(D) 300%

Correct Answer: [D] 300%

 Correct Answer: [B]

Correct Answer: B

94. Two cars, passing each other at high speed, are in danger of side swiping because

(A) of the increase in air pressure in the space between them.

(B) of a decrease in the velocity of air molecules between them.

(C) of a decrease in air pressure in the space between them.

(D) of the increase in the velocity of air molecules between them.

Correct Answer: [C] of a decrease in air pressure in the space between them.

95. The food that gives more calories per unit mass of food is

(A) protein

(B) carbohydrates

(C) fat

(D) water

Correct Answer: [C] fat

96. ECG records

(A) rate of heartbeats

(B) potential difference

(C) ventricular concentration

(D) the volume of blood pumped

Correct Answer: [B] potential difference

97. Biogas consists of

(A) Carbon monoxide, Methane, and Hydrogen

(B) Carbon 'dioxide, Methane, and Hydrogen

(C) Carbon monoxide, Ethane, and Hydrogen

(D) Carbon dioxide, Ethane, and Hydrogen.

Correct Answer: [B] Carbon 'dioxide, Methane and Hydrogen.

98. Noise pollution is created if noise is in excess to

(A) 70-75 dB

(B) 50-60 dB

(C) 80-99 dB

(D) 40-65 dB

Correct Answer: [C] 80-99 dB

99. If persons addicted to alcohol, the liver gets damaged because of it

(A) has to detoxify the alcohol.

(B) stores excess of glycol.

(C) is over stimulated to secrete more bile.

(D) accumulates an excess of fats.

Correct Answer: [D] accumulates an excess of fats.

100. At magnetic poles, the angle of dip is

(A) 450

(B) 30°

(C) Zero

(D) 90°

Correct Answer: [D] 90°

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WBCS Prelims 2019 Answerkey Download:

Download WBCS Prelims 2019 answer key in PDF format. It contains 200 MCQ questions on Indian History, Indian National Movement, Indian Geography with Special Reference to West Bengal, General Science, Indian Polity and Economy, English, General Mental Ability, Current Events of National and International Importance.