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1.
A ship travelling towards a cliff receives the echo of its whistle receives the echo of its whistle after 3.5 seconds. If the speed of sound in air under the prevailing conditions is 250ms, how much closer is the ship to the cliff?
A
10m
B
350m
C
175m
D
125m
correct option: D
explanation:
Difference in time = 1 sec
Echo time = 1 2 = 0.5 sec
Difference of cliff from ship = 0.5 x 250
= 125m
2.
A hydrometer is an instrument for measuring the
A
a depth of water of water in a vessel
B
relative density of a Liquid by the method of flotation
C
relative density of a liquid by finding the apparent loss in weight
D
relative humidity of the air
correct option: B
explanation: A hydrometer is an instrument used to determine specific gravity. It operates based on the Archimedes principle that a solid body displaces its own weight within a liquid in which it floats. Hydrometers can be divided into two general classes: liquids heavier than water and liquids lighter than water.
3.
Which of the following statements about defects of vision is/are CORRECT?
I.
For a long sighted person, close objects appear blurred
II.
For a short sighted person, distant objects appear blurred
III.
Short sight is corrected by using a pair of converging lenses
A
I only
B
II only
C
I and II only
D
II and III only
correct option: C
explanation:
shotsighted person needs a concave lens and not convex lens so as to diverge the image which is formd in front of retina to focus on the retina...
4.
The refractive index of a liquid is 1.5. If the velocity of light in a vacuum is 3.0 x 10, the velocity of light in the liquid is
A
1.5 x 10
B
2.0 x 10
C
3.0 x 10
D
4.5 x 10
correct option: B
explanation:
We know that refractive index of light is defined by η=
speed of light in medium
speed of light in vaccum
η=
v
3×10
8
=1.5
v=2×10
8
m/s
5.
The linear expansivity of brass is 2 x 10-5C-1. If the volume of a piece of brass is 15.00cm3 at 00C, What is the volume at 100oC?
A.
16.03cm3
B.
16.00cm3
C.
15.09cm3
D.
15cm3
correct option:
explanation:
linear expansivity = V2−V1V1×Δθ
3 x 2 x 10-5 =V2−1515×(100−0)
V2 = 15.09cm3
