State what is meant by a Doppler shift and describe how it was used to study the movement of galaxies.

Doppler shift can be described as the fractional change in wavelength due to relative motion between an observer and a wave source. The wavelength of a line in the spectrum of light emitted by a distant region of space can be compared to the same line found by the same wave reproduced in a laboratory.Where a increase in wavelength is found between the observer and the distance galaxy, it can be deduced that the galaxy is moving away from the observer and visa versa if the there is a decrease in the relative wavelength. We can use a formula (Change in wavelength/original wavelength = velocity of distant galaxy/speed of light) to determine the relative velocity of a receding galaxy.

Answered by Zubin M. Physics tutor

1806 Views

See similar Physics A Level tutors

Related Physics A Level answers

All answers ▸

You are asked to find the Young modulus for a metal using a sample of wire. *(a) Describe the apparatus you would use, the measurements you would take and explain how you would use them to determine the Young modulus for the metal.


A cannon can fire a cannonball at 20m/s. A sandpit is placed at a distance of 40m away. At what angle should the cannon be fired in order for the cannonball to land in the sand.


Given a projectile is launched, from rest, at an angle θ and travels at a velocity V, what is the range and path of motion of the projectile? (Ignore air resistance.)


What is the definition of a moment?


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo
Cookie Preferences