Question

Two wires of equal lengths are made of the same material. Wire A has a diameter that is twice as that of wire B. If identical weights are suspended from the ends of these wires, the increase in length is [EAMCET 1983; MP PMT 1990; MP PET 1995]
A) Four times for wire A as for wire B B) Twice for wire A as for wire B C) Half for wire A as for wire B D) One-fourth for wire A as for wire B

Answer 1

correct answer is C of ur question

Answer 2

Answer:

(d)  

Explanation:    l = FL/AY so l is directly proportional to 1/r2

Given Diameter of A = 2 × Diameter of B ∴ rA = 2rB  ∴ (ℓA / ℓB) = (rB / rA)2  (ℓA / ℓB) = (1/4) i.e. ℓB = 4ℓA  ℓA = (ℓB / 4)