Question

two wires p and q have same length and material. the area of cross section of wire Q is twice as that of P if they are stretched by the same load find the ratio of stress on wire P and Q​

Answer 1

Young's modulus (Y)=FlAΔl⇒Δl=FlAY

where, A= area of cross-section of wire

Δl= change in the length of the wire,

l= length of the wire

and F= applied force.

According to the question, F,l and Y are same for both wires, i.e.

Δl∝1A...(i)

But m=ρV

where, ρ= density ,V= volume.

m=ρAl[∵V=A]]

m∝A...(ii)

From Eqs. (i) and (ii), we get

Δl1Δl2=A2A1=m2m1