10 Question-Answer on dispersion of light
1. Finger prints on paper are identified by sprinkling fluorescent power on it and observing it under
(a) Mercury light
(b) Sun light
(c) Infrared light
(d) Ultra violet light
Ans: (d)
2. Fraunhoffer’s lines commonly visible in the sun’s spectrum are examples of
(a) Line emission spectrum
(b) Line absorption spectrum
(c) Band emission spectrum
(d) Band absorption spectrum
Ans: (b)
3. The nature of sun’s spectrum is:
(a) Line spectrum
(b) Band spectrum
(c) Continuous spectrum
(d) Continuous spectrum with a few absorption lines
Ans: (d)
4. Which of the following colours is scattered minimum?
(a) Violet
(b) Blue
(c) Red
(d) Yellow
Ans: (c)
5. A prism has a refracting angle of 60˚. When placed in the position of minimum deviation, it produces a deviation of 30˚. The angle of incidence is
(a) 30˚
(b) 45˚
(c) 15˚
(d) 60˚
Ans: (b)
6. The refractive indices of violet and red light are 1.54 and 1.52 respectively. If the angle of prism is 10˚, the angular dispersion in degree is :
(a) 0.02
(b) 0.20
(c) 3.06
(d) 30.6
Ans:(b)
7. The colour of a star is an indication of its
(a) Weight
(b) Distance
(c) Temperature
(d) Size
Ans: ( c)
8. Emission of light stops as the incident light is cut off in
(a) Phosphorescence
(b) Fluorescence
(c) Luminescence
(d) Efflorescence
Ans: (b)
9. Infra-red spectrum lies between
(a) Radio wave and microwave region
(b) The microwave and visible region
(c) The visible and ultra-violet region
(d) The ultraviolet and X-ray
Ans: (b)
10. The spectrum emitted by an incandescent solid is
(a) Continuous spectrum
(b) Discrete line spectrum
(c) Discrete band spectrum
(d) Spectrum similar to the Fraunhofer lines
Ans: (a)