Question

Q]A wire of length L, area of cross section A is hanging from a fixed support. The length of the wire changes to L₁ when mass M is suspended from its free end. The expression for Young’s modulus is

(a) MgL
₁ /AL

(b) Mg(L₁ - L)
/AL

(c) MgL
/AL₁

(d) MgL
/A(L₁ - L)
​

Answer 1

Answer:

OPTION C IS CORRECT

Explanation:

The initial length of the wire is L and the new length is L

1

.

We know that the Young's modulus is given as:

Y=

AΔl

FL

o

Here, L

o

is the initiallength of wire and Δl is the chnage in length of wire.

Substitute the values:

Y=

A×(L

1

−L)

mg×L

So, Y=

A(L

1

−L)

mgL

So, option C is correct.