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

Page 5

255241. The liquid/liquids used in simple barometer is/are
A
water
B
mercury
C
alcohol
D
all of the above
B
151342. An object moving with constant speed on a horizontal surface will not have
A
Kinetic energy
B
Acceleration
C
Velocity
D
Momentum
B
157743. Bats can fly in the dark without hitting objects because
A
They are guided by ultrasonic waves which they produce.
B
Of no scientific reason.
C
They are flying mammals.
D
Their night vision is good
A
Correct Answer: A. They are guided by ultrasonic waves which they produce.
151944. The ratio of the velocity of a body to the velocity of sound is called
A
Natural number
B
Mach number
C
Magic number
D
Laplace number
B
145845. A balloon filled with hydrogen bursts on reaching high altitude because
A
The surface of the balloon gets melted
B
It is a natural phenomenon
C
The pressure inside the balloon becomes less
D
The pressure inside the balloon becomes more.
D
Correct Answer: D. The pressure inside the balloon becomes more.
149946. 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.
B
152847. When loaded and empty trucks of identical specifications, are moving with the same velocity, more force is required to stop the loaded truck. Which of the following Laws is proved by this action?
A
Newton's third law of motion
B
Gravitational law
C
Newton's first law of motion
D
Newton's second law of motion
D
Correct Answer: D. Newton's second law of motion
A
Range Detection Appliance for Airplane Ranging
B
C
D
C
150049. Dyne sec. stands for the unit of
A
Energy
B
Power
C
Force
D
Momentum.
D
154750. The approximate intensity level of sound in dB which can causes damage to the eardrum is
A
140 dB
B
130 dB
C
120 dB
D
160 Db
A