Question

when the wire is compressed and its radius becomes 2R then its resistance will be?​

Answer 1

Explanation:

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Answer 2

Given: When wire is compressed, its Radius becomes 2R

To find: The new resistance of the wire

Explanation: When the wire is compressed, the length decreases and area increases but the volume is constant.

Let R1=R, R2 =2R, length before compression= L

Keeping volume constant,

Area1 * L = Area2* L2

=> πR^2 * L = π(2R)^2 * L2

=> L = 4 L2

=> L2 = L/4

Let resistivity be denoted as p.

Now,

resistance before compression(r)= pL/A

= pL/πR^2

Resistance after compression= pL2/A2

= p(L/4)/π (2R)^2

= 16 pL/π R^2

= 16 r

Therefore, the new resistance will be 16 times the resistance before compression.