Question

10. A wire of resistance 1 ohm is stretched so as
to change its diameter by 0.25%. The
percentage change in its resistance is​

Answer 1

Answer:

ANSWER

On stretching volume (V) remains constant.

So, V=Al

or, l=AV

R=ρ.Al

=ρ.A2V=π2D4/16ρV

=π2D416ρV

Taking logarithm of both sides and differentiating, we get

RΔR=−4DΔD

or RΔR=−4×025=1.0%

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