Question

In telescopes for a given wavelength, the objectives with large aperture are used for

• A. greater resolution.
• B. reducing lens aberration.
• C. greater magnification.
• D. ease of manufacture.

Hint:

Resolving power of a telescope is \(\dfrac{D}{1.22\lambda}\), so it grows with aperture \(D\).

Answer 1

The Correct Option is A

Step 1: Use the diffraction limit
$\Delta\theta\propto\dfrac{\lambda}{D}$.

Step 2: Conclude
For fixed $\lambda$, larger $D$ gives a finer resolution, option (A).

Final Answer:
Greater resolution, option (A). \[ \boxed{\text{Greater resolution}} \]