Question

A pulsar is a type of rotating neutron star that emits a beam of electromagnetic radiation. Imagine a pulsar that is moving toward Earth at a speed of 880.500 km/s. It emits mostly radio waves with a wavelength (at the source) of 123.500 cm. What is the observed wavelength of this radiation on Earth? (Assume the Earth is stationary. Consider the speed of light c = 3.00000 108 m/s. Give your answer to at least six significant figures.)

Answer 1

123.4994673cm

Step-by-step explanation:

In Doppler effect of light, frequency-source and frequency-observed are related by.

`f_o = f_s\beta` where
`$$\beta = \frac{1}{\sqrt{1-(v_s^2)/(c^2) } } $$`

And frequency is related to wavelength by.
`f = (c)/(L)` L is wavelength. and c is speed of light = 299792458m/s.

Now using this relationship, frequency source is = 242747976.5Hz.

and plugging this into f-source and f-observed relationship with V source = 880.500km/s = 880500m/s.

We get f observed is = 242747976.6Hz which when converted to wavelength gives L = 123.4994673cm.