The human eye and the colourful world Worksheet-3

The human eye and the colourful world Worksheet-3

 

  1. Which of the colours of visible light has minimum frequency?

A. violet              B. red                  C. yellow            D. green

 

  1. In which spectrum, there is no overlapping of colours ?

A. pure spectrum                         B. impure spectrum

 

  1. The broad wavelength range of visible spectrum is

A. 4000 – 8000 Å                       B. 2000 Å  – 4000 Å

C. 10000 – 20000 Å                   D. none of these

 

  1. All the colours of visible light travel with the same speed in air/vacuum. The statement is

A. true                B. false

 

  1. Which colour has maximum speed in glass ?

A. violet              B. red                  C. yellow            D. green

 

  1. For which colour, refractive index of glass is maximum ?

A. red                  B. violet              C. green             D. yellow

 

  1. Which colour suffers least deviation on passing through a prism ?

A. red                  B. violet              C. indigo            D. blue

 

  1. Scattering of light involves

A. reflection                                   B. refraction

C. diffraction                                 D. change in direction of light.

 

  1. The amplitude of scattered light varies with wavelength λ as

A.               B.               C.              D.

 

  1. The intensity of scattered light varies with amplitude (a) of scattered light as

A.                B.              C.                 D.

 

  1. The intensity of scattered light varies inversely as nth power of wavelength (λ) of incident light where

A. n = 2              B. n = 1               C. n = 4              D. n = –4

 

  1. Blue colour of sky is due to

A. scattering of light                    B. reflection of light

C. refraction of light                    D. diffraction of light.

 

  1. For Rayleigh elastic scattering, size of scatterer (x) should be

where λ is wavelength of incident light.

A. x ≈ λ               B. x > λ               C. x >> λ            D. x << λ

 

  1. Red colour of sun at the time of sunrise and sunset is because

A. Red colour is least scattered.

B. Blue colour is least scattered.

C. Red colour is scattered the most.

D. All colours are equally scattered.

 

  1. Twinkling of stars is due to

A. reflection                                  B. dispersion

C. atmospheric refraction          D. none of these

 

Answer Key:

  1. B

Explanation: Red colour has largest wavelength and hence the minimum frequency.

  1. A
  2. A

Explanation: The broad wavelength range of visible spectrum is 4000 Å – 8000 Å.

  1. A
  2. C
  3. B

Explanation:  

  1. A

Explanation: Red colour is at the upper end of the spectrum. It suffers least deviation.

  1. D

Explanation: Scattering of light involves change in direction of light on striking a scatterer.

  1. C

Explanation: Amplitude of scattered light,

  1. A

Explanation:

  1. C

Explanation:

  1. A

Explanation:

  1. D

Explanation: For Rayleigh elastic scattering, x << λ

  1. A

    Explanation: As wavelength λ of red colour is largest and therefore, red colour is least scattered. It enters into our eyes and the sun looks reddis

  2. C