Question

Explanation is required. Ans:a Please don't spam.

Answer 1

Given:

A sine wave snapshot has been taken and 4 elemental portions (a, b, c and d ) have been marked.

To find:

The elemental portion having the maximum potential energy.

Concept:

Usually , students consider this wave consisting of Oscillatory particles undergoing SHM ; hence they often mistakenly get the answer as "b and d" because SHM has highest Potential Energy at the extremes.

But the actual reason is as follows :

Since we are looking at a snapshot of a travelling wave (and not a travelling wave itself) , we have to consider the STRAIN ENERGY enclosed by the elemental portions.

Elemental portion "a" experiences maximum strain from both sides in opposite direction. Hence it has max Strain energy , which is a type of Potential Energy.

Diagram:

Refer to the attached photo to understand the strain experienced by elemental portion "a".

So final answer :

$\boxed{ \sf{ \bold{ \large{ \red{max \: potential \: energy = a}}}}}$