Physics: Light MCQ Quiz 4

Question 1. If the lens power of glass is +2 dioptre, its focal length will be_______.

(A) 2 cm

(B) 50 cm

(C) 100 cm

(D) 200 cm

Question 2. The power of a lens is measured in________.

(A) Candela

(B) Lumen

(C) Aeon

(D) Dioptre

Question 3. Which one of the following combinations of aperture and shutter speed of a camera will allow the maximum exposure?

(A) f-5.6, 1/1000

(B) f-8, 1/250

(C) f-16, 1/125

(D) f-22, 1/60

Question 4. Retina of the eye is comparable to which of the following parts of a traditional camera?

(A) Cover

(B) Shutter

(C) Lens

(D) Film

Question 5. In human eye, image of object forms at ______.

(A) Retina

(B) Pupil

(C) Iris

(D) Cornea

Question 6. Power of Sunglass is_____.

(A) 4 dioptre

(B) 2 dioptre

(C) 1 dioptre

(D) 0 dioptre

Question 7. The colour of an opaque object is due to the colour it____.

(A) Scatters

(B) Reflects

(C) Refracts

(D) Absorbs

Question 8. Colour in a colour television is produced by a combination of three basic colours, they are_______.

(A) Red, green and brown

(B) Red, yellow and green

(C) Red, green and blue

(D) Red, blue and orange

Question 9. The minimum distance of clear vision for a normal healthy eye of human being is supposed to be________.

(A) 25 cm

(B) 15 cm

(C) 10 cm

(D) 50 cm

Question 10. Which is not a primary colour?

(A) Blue

(B) Red

(C) Yellow

(D) Black

Question 11. Consider the following statements.

1. If a person looks at a coin which is in a bucket of water, the coin will appear to be closer than it really is.
2. If a person under water looks at a coin above the water surface, the coin will appear to be at a higher level than it really is.

Which of the above statements is/ are correct?

(A) Neither 1 nor 2

(B) Only 2

(C) Only 1

(D) 1 and 2

Question 12.

• Assertion(A): A stick is dipped in water in a slanting position. If observed sideways, the stick appears short and bent at the surface of the water.
• Reason(R): A light coming from the stick undergoes scattering from water molecules giving the stick a short and bent appearance.

(A) (A) is false, but (R) is true

(B) (A) is true, but (R) is false

(C) Both (A) and (R) are true, but (R) is not the correct explanation of (A)

(D) Both (A) and (R) are true and (R) is the correct explanation of (A)

Question 13. Rainbow is produced when Sunlight falls on drops of rain, which of the following physical phenomena are responsible for this?

1. Dispersion
2. Refraction
3. Internal reflection

Select the correct answer using the code given below.

(A) 1 and 2

(B) 1 and 3

(C) 2 and 3

(D) All of the above

Question 14.

• Assertion(A): Small glass beads fixed on traffic signals glow brightly when light falls upon them.
• Reason(R): Light is totally reflected when the angle of incidence exceeds a certain critical value and light travelling in a denser medium is reflected from a rarer medium. 

(A) (A) is false, but (R) is true

(B) (A) is true, but (R) is false

(C) Both (A) and (R) are true, but (R) is not the correct explanation of (A)

(D) Both (A) and (R) are true and (R) is the correct explanation of (A)

Question 15. Consider the following statements.

1. The sky appears blue because of less scattering.
2. The main cause of seven colours of the rainbow is scattering of light.
3. At the time of Sunrise, the Sun appears red, due to scattering of light.

From the following statements.

(A) 2 and 3 are true

(B) Only 2 is true

(C) 1 and 3 are true

(D) Only 1 is true

Question 16.

• Assertion (A): The danger signal is made up of red colour.
• Reason (R): Red colour is scattered the least.

Select the correct answer using the codes given below.

(A) (A) is false, but (R) is true

(B) (A) is true, but (R) is false

(C)  Both (A) and (R) are true, but (R) is not the correct explanation of (A)

(D) Both (A) and (R) are true and (R) is the correct explanation of (A)

Question 17.

• Assertion (A): In the visible spectrum of light, red light is more energetic than green light.
• Reason (R): The wavelength of red light is more than that of green light.

(A) (A) is false, but (R) is true

(B) (A) is true, but (R)  is false

(C) Both (A) and (R) are true, but (R) is not the correct explanation of (A)

(D) Both (A) and (R) are true and (R) is the correct explanation of (A)

Question 18. Consider the following statements.

1. If magenta and yellow coloured circles intersect, the intersected area will have a red colour.
2. If cyan and magenta coloured circles intersect, the intersected area will have a blue colour.

Which of the statements given above is/are correct?

(A) Neither 1 nor 2

(B) Both 1 and 2

(C)  Only 2

(D) Only 1

Question 19.

• Assertion (A): In a motion picture, usually 24 frames are projected every second over the whole length of the film.
• Reason (R): An image formed on the retina of eye persists for about 0.1s after the removal of the stimulus. 

(A) (A) is false, but (R) is true

(B) (A) is true, but (R) is false

(C) Both (A) and (R) are true, but (R) is not the correct explanation of (A)

(D) Both (A) and (R) are true and (R) is the correct explanation of (A)

Question 20. Consider the following statements.

1. Light of longer wavelength is scattered much more than the light of shorter wavelength.
2. The speed of visible light in water is 0.95 times the speed in vacuum.
3. Radio waves are produced by rapidly oscillating electrical currents.
4. To detect the overspeeding vehicles, police use the Doppler effect of reflected short radio waves.

Which of these statements are correct? 

(A) 3 and 4

(B) 2 and 4

(C) 1 and 3

(D) 1 and 2

Question 21. Given below are two statements, one labelled as Assertion (A) and other labelled as Reason (R).

• Assertion (A): A diamond sparkles more than a glass imitation cut to the same shape.
• Reason (R): The refractive index of diamond is less than that of glass.

In the context of the above two statements, which one of the following is correct?

(A) (A) is false, but (R) is true

(B) (A) is true, but (R) is false

(C) Both (A) and (R) are true, but (R) is not the correct explanation of (A)

(D) Both (A) and (R) are true and (R) is the correct explanation of (A)

Question 22. Consider the following natural phenomena.

1. Terrestrial heating
2. Reflection of light
3. Refraction of light
4. Diffraction of light

Due to which of these phenomena is mirage formed?

(A) Only 4

(B) 1 and 3

(C) 2, 3 and 4

(D) 1 and 2

Question 23. Consider the following statements.

1. Fibre optics is based on the principle of total internal reflection.
2. In an optical fibre communication system, power consumption is extremely low.
3. Optical fibre communications are free from radio frequency interference.
4. In India, Reliance Group of Industries is engaged in the manufacture of optical fibre.

Which of these statements are correct? 

(A) 2, 3 and 4

(B) 1, 3 and 4

(C) 1, 2 and 4

(D) 1, 2 and 3

Question 24. Consider the following phenomena.

1. Size of the Sun at dusk
2. Colour of the Sun at dawn
3. Moon being visible at dawn
4. Twinkle of stars in the sky
5. Polestar being visible in the sky

Which of the above are optical illusions?

(A) 2, 3 and 5

(B) 1, 2 and 4

(C) 3, 4 and 5

(D) 1, 2 and 3

Question 25. Find out the odd colour from the following options______.

(A) Yellow

(B) Red

(C) Brown

(D) Green

Question 26. The number of colours contained in the Sunlight is ?

(A) 7

(B) 6

(C) 5

(D) 3

Question 27. Three colours are the primary colours. These are_______.

(A) Blue, Yellow and Red

(B) Yellow, Green and Red

(C) Blue, Green and Red

(D) Blue, Yellow and Red