Question

Draw a ray diagram for a reflecting telescope. Explain its working and compare it with a refracting telescope.

Answer 1

Step 1: Ray Diagram for Reflecting Telescope.

In a reflecting telescope, a concave mirror is used to gather and focus light. The diagram is shown below:

Step 2: Working of a Reflecting Telescope.
In a reflecting telescope: 
1. Light from a distant object enters the telescope and strikes the concave mirror. 
2. The concave mirror reflects the light and focuses it at the focal point. 
3. The eyepiece lens is placed at the focal point, and it magnifies the image formed by the mirror.

Step 3: Comparison with Refracting Telescope.
In a refracting telescope, lenses are used instead of mirrors. The light enters the objective lens, which forms an image. This image is then magnified by the eyepiece lens. Unlike the reflecting telescope, the refracting telescope uses the lens’s refraction instead of reflection. 

Final Answer:
A reflecting telescope uses a concave mirror to gather and focus light, while a refracting telescope uses lenses. Reflecting telescopes are generally preferred in astronomy due to the absence of chromatic aberration.