Refraction of Light Quiz - CBSE Class 12 Physics

Free practice quiz: Refraction of Light (CBSE Class 12 Physics). 16 multiple-choice questions with answers and explanations. Play online, no sign-up needed.

Sample questions

1. A ray of light passes from air into glass. Which of the following statements is true?

   1. The speed of light increases.
   2. The frequency of light changes.
   3. The wavelength of light increases.
   4. The wavelength of light decreases.
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   Answer: D. The wavelength of light decreases.

   When light passes from a rarer medium (air) to a denser medium (glass), its speed decreases. Since the frequency of light remains constant, the wavelength must decrease according to the relation v = fλ (where v is speed, f is frequency, and λ is wavelength).

2. What is the critical angle?

   1. The angle of incidence at which the angle of refraction is 90°.
   2. The angle of refraction at which the angle of incidence is 90°.
   3. The angle at which total internal reflection occurs.
   4. The angle at which light is completely absorbed.
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   Answer: A. The angle of incidence at which the angle of refraction is 90°.

   The critical angle is defined as the angle of incidence in the denser medium for which the angle of refraction in the rarer medium is 90°.

3. Explain how the refractive index of a liquid can be determined using a spectrometer.

   1. By measuring the angle of minimum deviation.
   2. By measuring the angle of incidence.
   3. By measuring the angle of refraction.
   4. By measuring the critical angle.
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   Answer: A. By measuring the angle of minimum deviation.

   A spectrometer can be used to precisely measure the angle of minimum deviation for a prism made of the liquid. This angle is then used to calculate the refractive index of the liquid using the prism formula.

4. What is the phenomenon responsible for the twinkling of stars?

   1. Diffraction of starlight
   2. Interference of starlight
   3. Refraction of starlight
   4. Reflection of starlight
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   Answer: C. Refraction of starlight

   The twinkling of stars is due to atmospheric refraction of starlight. The density of air in the atmosphere fluctuates, causing the light to bend slightly in varying amounts, resulting in the apparent twinkling.

5. Explain the phenomenon of mirage.

   1. Due to scattering of sunlight
   2. Due to total internal reflection of light
   3. Due to refraction of light
   4. Due to diffraction of light
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   Answer: C. Due to refraction of light

   Mirages are an optical illusion caused by refraction of light. The density of air near the ground changes with temperature, creating layers with different refractive indices. This causes light rays to bend, creating the appearance of water or other objects.

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