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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 704.500 km/s. It emits mostly radio waves with a wavelength (at the source) of 133.500 cm. What is the observed wavelength of this radiation on Earth

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Answer:


\lambda_o=133.4994\ cm

Step-by-step explanation:

Given:

speed of light source towards the earth,
v=7.045* 10^5\ m.s^(-1)

wavelength of the light emitted by the source,
\lambda_s=133.5\ cm

We know the speed of electromagnetic waves is,
c=3*10^8\ m.s^(-1)

Here since the speed of the source is comparable to the speed of light, we've:

For the doppler effect of EM waves:


(\lambda_o)/(\lambda_s) =\sqrt{(1-(v)/(c) )/(1+(v)/(c) )}


(\lambda_o)/(133.5)=\sqrt{(1-(7.045* 10^5)/(3*10^8))/ (1+(7.045* 10^5)/(3*10^8))}


\lambda_o=133.4994\ cm

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