Question

A transverse wave is travelling along a string from left to right. The figure below represents the shape of the string at a given instant. At this instant, among the following, choose the wrong statement –

• A. Points D, E, F have upwards positive velocity
• B. Points A, B and H have downwards negative velocity
• C. Point C and G have zero velocity
• D. Points A and E have minimum velocity

Answer 1

Answer: (D)

Points A and E have minimum velocity

Answer 2

We have U = – $\frac{vdy}{dx}$

(1) $\frac{dy}{dx}$Ž i.e slope is the for D, E, F is –ve, so

U ® +ve means moving upward

(2) $\frac{dy}{dx}$Ž +ve at A, B, H

(3) $\frac{dy}{dx}$= 0 at C and G

(4) $\frac{dy}{dx}$Ž maximum at A and E, so velocity will also be maximum