First slide

Ray optics

Question

In an electron microscope, the accelerating voltage is increased from 20 kV to 80 kV. If resolving power of 20 KV is R, the resolving power for 80 KV is

Moderate

A

R/2
B

1R
C

3R
D

2R

Solution

From the electron, $\frac{p^{2}}{2 m} = e V \Rightarrow p = \sqrt{2 m e V}$
$∴ λ = \frac{h}{p} = \frac{h}{\sqrt{2 m e V}} \Rightarrow λ \propto \frac{1}{\sqrt{V}}$
Now resolving power $R \propto \frac{1}{λ} \Rightarrow R \propto \sqrt{V}$
$∴ \frac{R^{1}}{R} = \sqrt{\frac{80}{20}} = 2 \Rightarrow R^{1} = 2 R$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App