If the peak wavelength of a star at rest is 1375 nm, then what peak wavelength is observed when the star is traveling 975,000 m/s away from the earth.

The concept required to solve this problem is that of the Doppler effect which is defined as the change in frequency of a wave in relation to an observer who is moving relative to the wave source

Mathematically it can be expressed as

Where,

c = Speed of light

= Peak wavelength

= Peak Wavelength observed

Our values are given as,

Speed of light

Basically what we should look for is that 'relative' frequency that is emitted when the star moves away so we clear

Replacing we have,

Therefore the peak wavelength that is observed when the star is traveling away from the eart to the velocity given is 1379.46nm

c

explanation: