Physics

Problem

Rigidity modulus and Young's modulus are respectively

\eta

and

Y

. A copper wire of length

L

and area of cross-section

A

is so pulled that its length becomes

5L

and area of cross-section becomes

(\frac{A}{5})

. So, (A) its

Y

increases,

\eta

decreases. (B) Its

\eta

increases,

Y

decreases. (C) its

Y

and

\eta

both increases. (D) It's

Y

and

\eta

both remain unchanged.