wave_mechanics critical_thinking Question 3

Question: The ends of a stretched wire of length L are fixed at $ x=0 $ and $ x=L. $ In one experiment, the displacement of the wire is $ y _{1}=A\sin (\pi x/L)\sin \omega t $ and energy is $ E _{1} $ , and in another experiment its displacement is $ y _{2}=A\sin (2\pi x/L)\sin 2\omega t $ and energy is $ E _{2} $ . Then

[IIT-JEE (Screening) 2001]

Options:

A) $ E _{2}=E _{1} $

B) $ E _{2}=2E _{1} $

C) $ E _{2}=4E _{1} $

D) $ E _{2}=16E _{1} $

Show Answer

Answer:

Correct Answer: C

Solution:

Energy (E) ยต (Amplitude)2 (Frequency)2 Amplitude is same in both the cases, but frequency 2$ \omega $ in the second case is two times the frequency $ (\omega ) $ in the first case.

Hence $ E _{2}=4E _{1} $ .



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