WBCHSE Class 12 Physics Dispersion Of Light Multiple Choice Questions

Dispersion Of Light Multiple Choice Questions

Question 1.  A passenger in an aeroplane

1. A shall never see a rainbow
2.  May see a primary and secondary rainbow as concentric circles
3.  May see a primary and secondary rainbow as concentric arcs
4. Shall never see a secondary rainbow

Answer: 2.  May see a primary and secondary rainbow as concentric circles

Question 2. Between the primary and secondary rainbow there dark band known as Alexander’s dark band thisbecause

1. Light scattered into this region interferes destructively
2. There is no light scattered into this region
3. Light is absorbed in this region
4. The angle made at the eye by the scattered rays with respect to the incident light of the sun lies between approximately 42° and 50°

Answer: 1 And 4

Question 3. Among the following colours of light whose velocity is maximum while passing through a glass slab?

1. Red
2. Blue
4. Yellow
5. Violet

Answer: 1. Red

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Question 4. Which one Is not a dispersive medium

1. 4. Water
2. Glass
3. Air
4. Glycerine

Answer:  3. Air

Question 5. The limit of wavelength of visible light

1. 3000 μm to 0.4μm
2. 0.7μm to 1000 μm
3. 0.4 μm to 0.8μm
4. 0.1cm to 30cm

Answer: 0.4 μm to 0.8μm

Question 6. Focal length of n Ions is

1. Same for all wavelengths
2. Muxinnim for red and minimum for violet
3. Zero for red and infinite for violet
4. Maximum for violet and minimum for red

Answer: 2. Muxinnim for red and minimum for violet

Question 7. The refractive indices of two prisms, for two rays of light, and 1.66 and 1,64 respectively. The dispersive power of the prism is

1. 0.02
2. 0.012
3. 0.010
4. 0.03

Answer: 0.03

Question 8. The refractive index of the material of a prism, for violet and red light, are 1.66 and 1.64 respectively. If the refracting angle of the prism be 10°, then the angular dispersion for these two colours are

1. 0.20°
2. 0.10°
3. 0.40°
4. 1°

Answer: 0.20°

Question 9. The two colours of light for which angular dispersion is maximum are

1. Yellow and green
2. Red and blue
3. Green and Red
4. Blue and Orange

Question 10. The refractive index of a substance for blue light is 1.67, for yellow 1.65 and for red light 1.63. The dispersive power of the substance

1. 0.031
2. 1.60
3. 0.0615
4. 0.024

Answer:  3. 0.0615

Question 11. Spectrum that a red hot heater produces

1. Continuous
2. Band
3. Line
4. Absorption

Answer: Continuous

Question 12. The spectrum that contains all ranges of frequency—from high to low, is

1. Band spectrum
2. Line spectrum
3. Continuous spectrum
4. Line-absorption spectrum

Answer: 2. Line spectrum

Question 13. A spectrum which contains all wavelengths without any break is called

1. Emission spectrum
2. Line spectrum
3. Continuous emission spectrum
4. All of these

Answer: 3. Continuous emission spectrum

Question 14. Solar spectrum is

1. Continuous emission spectrum
2. Continuous absorption spectrum
3. Line spectrum
4. Band absorption spectrum

Answer:  1. Continuous emission spectrum

Question 15. Fraunhofer spectrum is

1. Line absorption spectrum
2. Band absorption spectrum
3. Line emission spectrum
4. Band emission spectrum

Answer: 1. Line absorption spectrum

Question 16. A green object illuminated by yellow light will look

1. Red-colour
2. Yellow
3. Black
4. Green

Answer: 3. Black

Question 17. If a red glass is placed in between a source of white light and a green screen, the colour of the screen will be

1. Red
2. Green
3. Black
4. Yellow

Answer: 3. Black

Question 18. How would the sky look in the absence of atmosphere?

1. Blue
2. Violet
3. White
4. Black

Answer: 4. Black

Question 19. What colour of light is used as a danger signal?

1. Green
2. Red
3. Yellow
4. Violet

Answer: 2. Red

Question 20. The continuous emission spectrum is produced by

1. Vapour lamp
2. White hot molten Iron
3. A vacuum tube Containing oxygen at low-pressure
4. Filament of a glowing electric lamp

Answer: 2 And 4

Question 21. When a narrow beam of white light passes through a parallel slab

1. The light never splits into constituent colours
2. The light inside the slab splits into constituent colours
3. The emergent beam is white
4. The light inside the slab is white

Answer: 2 And 3

Question 22. By properly combining two prisms made of different materials, it is possible to

1. Have dispersion without average deviation
2. Have deviation without dispersion
3. Have both dispersion and average deviation
4. Have neither dispersion nor average deviation

Answer:  1, 2, And 3

Question 23. Rainbow is formed due to the combinational of

1. Refraction and scattering
2. Refraction and absorption
3. Dispersion and total internal reflection
4. Dispersion and focussing

Answer: 2 And 4

Question 24. The refractive indices of a material for red violet and blue light are respectively 1.52, 1.62 and 1.59.

1. The dispersive power of the material is

1. 0.0345
2. 0.0154
3. 0.1695
4. 0.0276

Answer:  3. 0.1695

2. If the mean deviation is 40°, the value of angular dispersion of a prism of the above material will be

1. 6.78°
2. 3.52°
3. 4.25°
4. 5.74°

Answer:  1. 6.78°

Question 25. The refractive indices of glass for red and blue light are 1.613 and 1.632 respectively

1. To send the beams of the two lights referred to above through a thin prism(A = 5°) made of the above glass the angular dispersion will be

1. 0.108°
2. 0.087°
3. 0.095°
4. 0.072°

Answer: 3. 0.095°

2. The dispersive power of the material of the prism will be

1. 0.0115
2. 0.0305
3. 0.0275
4. 0.0189

Answer:  2. 0.0305

Question 26. A parallel beam of white light falls on one face of a prism. The light emerging from the other face suffers

1. Angular deviation, no dispersion
2. Dispersion, no angular deviation
3. Both dispersion and angular deviation
4. None of these

Answer: 3. Both dispersion and angular deviation