Resolving Power (Rayleigh) — Practice Quiz

Question 1

A telescope has aperture 25 cm. The minimum angular separation it can resolve for λ = 500 nm is:

Accepted Answer

2.4 × 10⁻⁶ rad

Answer

1.2 × 10⁻⁶ rad

Answer

5 × 10⁻⁶ rad

Answer

5 × 10⁻⁵ rad

Question 2

Resolving power of a microscope can be increased by:

Accepted Answer

Using shorter wavelength

Answer

Increasing magnification only

Answer

Decreasing NA

Answer

Lengthening the tube

Question 3

Why is electron microscopy able to resolve atoms while optical microscopy cannot?

Accepted Answer

Electron de Broglie wavelength is much shorter than visible light

Answer

Electrons are smaller than atoms

Answer

Electrons are faster

Answer

Atoms emit electrons

Question 4

Two stars are just resolved by a telescope of aperture D. For finer resolution, you should:

Accepted Answer

Both increase D and decrease λ

Answer

Decrease D

Answer

Increase D

Answer

Decrease λ used (filter UV)

Question 5

The Rayleigh criterion gives θ_min = 1.22 λ/D. The factor 1.22 arises from:

Accepted Answer

First zero of Bessel function J₁

Answer

Refractive index of air

Answer

First minimum of sinc²

Answer

Numerical aperture