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A periscope uses two plane mirrors inclined at 45^ . If the tube of the periscope is filled with a complete transparent liquid of refractive index 1.5 , then which one of the following is correct in respect of the image seen?

Options

  1. AThe image will remain unchanged.
  2. BThe image will appear laterally shifted.
  3. CThe image will appear 1.5 times brighter.
  4. DThe image will appear 1.5 times darker.

Correct answer

A. The image will remain unchanged.

Step-by-step solution

The working of a periscope is based on the successive reflections of light from two plane mirrors placed parallel to each other and inclined at an angle of 45^ . The image formation by a plane mirror is governed by the laws of reflection, which state that the angle of incidence is equal to the angle of reflection. These laws are entirely independent of the refractive index of the surrounding medium. When the tube of the periscope is filled with a completely transparent liquid of refractive index 1.5 , the light ray

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