Question

A source at rest emits light of wavelength 500 nm. When it is moving at 0.90c toward an observer, the observer detects light of wavelength: 26 nm 115 nm 500 nm 2200 nm 9500 nm

Answer 1

The observer detects light of wavelength is 115 nm.

(b) is correct option

Step-by-step explanation:

Given that,

Wavelength of source = 500 nm

Velocity = 0.90 c

We need to calculate the wavelength of observer

Using Doppler effect

`\lambda_(o)=\sqrt{(1-\beta)/(1+\beta)}\lambda_(s)`

Where,
`\beta=(c)/(v)`

`\lambda_(o)=\sqrt{(c-0.90c)/(c+0.90c)}*500*10^(-9)`

`\lambda_(o)=115\ nm`

Hence, The observer detects light of wavelength is 115 nm.