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JEE Main20238 Apr 2023Morning ShiftPhysicsRay OpticsActual

In a reflecting telescope, a secondary mirror is used to:

Options

  1. Areduce the problem of mechanical support
  2. Bmake chromatic aberration zero
  3. Cmove the eyepiece outside the telescopic tube
  4. Dremove spherical aberration

Correct answer

C. move the eyepiece outside the telescopic tube

Step-by-step solution

Mirrors are used in reflecting telescopes, which allow astronomers to see distant objects in space more clearly. A mirror forms an image by gathering light from spatial objects. A second mirror receives the picture that was reflected by the first mirror, which may be rather wide. The light is reflected by this tiny mirror onto an eyepiece lens, which magnifies or enlarges the image of the object. Hence, the secondary mirror is used to move the eyepiece outside the telescopic tube.

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