Q. 79

Expert-verified
Found in: Page 454

Physics for Scientists and Engineers: A Strategic Approach with Modern Physics

Book edition 4th
Author(s) Randall D. Knight
Pages 1240 pages
ISBN 9780133942651

Wavelengths of light from a distant galaxy are found to be0.50% longer than the corresponding wavelengths measured in a terrestrial laboratory. Is the galaxy approaching or receding from the earth? At what speed?

The galaxy is receding at a speed of

See the step by step solution

Step 1: Given data

the detected wavelengths of light from a distant galaxy islonger than the actual wavelength. So, the measured wavelength is,

Step 2: Determination of speed

The Doppler effect for receding light waves, the detected wavelength is longer than the emitted wavelength by the source.

Here according to the question, the detected wavelengths of light from a distant galaxy islonger than the actual wavelength. So, the galaxy is receding away.

Consider the galaxy has a speed of

Now, according to the equation of detected wavelength of receding light wave,