# Physics MCQs GK objective Questions GK test Set – 39

## Question 1.

Which Color has the Longest Wavelength?

A. Violet
B. Yellow
C. Red
D.White

Ans: C. Red

## Question 2.

Rainbows are produced when sunlight :

A. Incident on rain drops hanging in the atmosphere is dispersed after suffering refraction
B. Incident on rain drops hanging in the atmosphere is dispersed after suffering refraction and internal reflection.
C. Incident on raindrops hanging in the atmosphere is dispresed after suffering reflection.
D. None of the given statements is correct.

Ans: B. Incident on rain drops hanging in the atmosphere is dispersed after suffering refraction and internal reflection.

## Question 3.

Which one of the following instruments is used to study dispersion of light ?

A. Microscope
B. Telescope
C. Spectrometer
D. Photometer

Ans: C. Spectrometer

## Question 4.

How much calorie of energy is released by a boiled egg ?

A. 40
B. 50
C. 60
D. 77

Ans: D. 77

## Question 5.

The colour of sky appears blue due to

A. Reflection
B. Refraction
C. Scattering of shorter wave lengths
D. Dispersion

Ans: C. Scattering of shorter wave lengths

## Question 6.

Red light is used for signals because it has

A. Long wavelength
B. High intensity
C. High frequency
D. Low refraction in the medium

Ans: A. Long wavelength

## Question 7.

Which one of the following is responsible for the working of Newton’s colour disc experiment ?

A. Formation of pure spectra
B. Formation of impure spectra
C. Persistence of vision
D. Principle of complementary colour

Ans: C. Persistence of vision

## Question 8.

A stone is dropped from the roof of a house towards the ground. The kinetic energy of the stone will be maximum:

A. Just after it is dropped
B. When it is just on the half-way
C. Just before it touches the ground
D. When it touches the ground

Ans: C. Just before it touches the ground

## Question 9.

Sun appears red in colour at sunrise and sunset due to

A. The fact that sun emits only red colour at that time
B. Red light having longer wave length scatters away
C. That sun comes out of the mountains
D. That all other colours scatter away except red

Ans: D. That all other colours scatter away except red

## Question 10.

Why does the sea appear blue in colour?

A. Reflection of the sun light from water surface
B. Interference of the sun light from water surface
C. Scattering of the sunlight by water molecules
D. Refraction of the sun light

Ans: C. Scattering of the sunlight by water molecules

## Question 11.

An object which absorbs all colours and reflects none appears:

A. White
B. Grey
C. Blue
D. Black

Ans: D. Black

## Question 12.

A 4 kg object is moving horizontally with a speed of 5 m/s. To increase its speed to 10 m/s, the amount of net work required to be done on this object is:

A. 150 J
B. 100 J
C. 50 J
D. 75 J

Ans: A. 150 J

## Question 13.

Total number of colours exists in sunlight

A. 5
B. 7
C. 9
D. 10

Ans: B. 7

## Question 14.

The sky appears blue because

A. All colours interfere to produce blue
B. In white light, the blue component dominates
C. The atmosphere scatters blue colour more than the others
D. It is actually blue

Ans: C. The atmosphere scatters blue colour more than the others

## Question 15.

Microphone is a device which transforms the

A. Sound signal into current signal
B. Current signal into sound signal
C. Sound signal into light signal
D. Light signal into sound signal

Ans: A. Sound signal into current signal

## Question 16.

Gasoline is useful in cars because it has

A. Chemical potential energy
B. Electrical potential energy
C. Gravitational potential energy
D. Kinetic energy

Ans: A. Chemical potential energy

## Question 17.

When white light passes through a glass prism we get a spectrum on the other side of the prism. In the emergent beam the ray which is deviated least is

A. The violet ray
B. The red ray
C. The green ray
D. The blue ray

Ans: B. The red ray

## Question 18.

During washing of clothes, we use indigo due to its

A. Better cleaning action
B. Proper pigmental composition
C. High glorious nature
D. Very low cost

Ans: B. Proper pigmental composition

## Question 19.

Conversion of heat into electrical energy is achieved by using :

A. Ammeter
B. Hydrometer
C. Voltmeter
D. Thermocouple

Ans: D. Thermocouple

## Question 20.

Electric Motor converts __ energy to mechanical energy

A. Sound
B. Mechanical
C. Chemical
D. Electrical

Ans: D. Electrical

## Physics GK MCQs all set

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