Discussion Forum



1)

A block M hangs vertically at the bottom end of a uniform rope constant mass per unit length. The top end of the rope is attached to a fixed rigid support at O. A transverse wave pulse (pulse 1) of wavelength λ0 is produced at point O on the rope. The pulse takes time TOA to reach point A. If the wave pulse of wavelength λ 0  is produced at point A (pulse 2) without disturbing the position of M it takes time TAO to reach point O. Which of the following options is/are correct?

 17122019134_pulse.PNG

 


A) The time $T_{AO}=T_{OA}$

B) The wavelength of the pulse 1 becomes longer when it reaches point A

C) The velocity of any pulse along the rope is independent of its frequency and wavelength

D) The velocity of the two pulses (pluses1 and pulse 2) are the same at the midpoint of rope

Answer:

Option A,C,D OR A

Explanation:

$v=\sqrt{\frac{T}{\mu}}$   so the speed at any position will be same for both pulses, therefore the time taken by both pulses will be same

                    λf=v

                  $\lambda=\frac{v}{f}$

$\Rightarrow$     $λ \propto v \propto T$

since when pulse 1 reaches at A tension and hence speed decreases therefore λ decreases.