Q.

Under the same load, wire A having length 5.0 m and cross section 2.5×10-5 m2 stretches uniformly by the same amount as another wire B of length 6.0 m and a cross section of 3.0×10-5 m2 stretches. The ratio of the Young’s modulus of wire A to that of wire B will be              [2023]

1 1 : 4  
2 1 : 1  
3 1 : 10  
4 1 : 2  

Ans.

(2)

Δl=FlSY

Since F is same for both wires and Δl is also same

ΔlF=lSYlASAYA=lBSBYB

52.5×YA=63×YB

YAYB=1