Special theory of relativity — CSIR Net PYQ (Question 2)

A Special theory of relativity previous-year question (PYQ) from Classical Mechanics (CSIR Net). Read the question, check the correct answer, then practise the full topic.

Question 2 of 27 · 5.0 marks

A distant source, emitting radiation of frequency $\omega$ moves with a velocity $\frac{4c}{5}$ in a certain direction with respect to a receiver (as shown in the figure). The upper cut-off frequency of the receiver is $\frac{3\omega }{2}$. Let $\theta$ the angle as
shown. For the receiver to detect the radiation, $\theta$ should at least be

1. 1${cos}^{-1}\left(\frac{1}{2}\right)$
2. 2${cos}^{-1}\left(\frac{3}{4}\right)$
3. 3${cos}^{-1}\left(\frac{2}{\sqrt{5}}\right)$
4. 4${cos}^{-1}\left(\sqrt{\frac{2}{3}}\right)$

Correct answer: Option 2

About this question

This Special theory of relativity PYQ is part of the Classical Mechanics section of CSIR Net. Browse more Special theory of relativity questions or join the PhysicsByAaryan live batch for full conceptual coverage.