Question

A wire had a resistance of 20 ohm. It was then melted and reduced to one fifth of it's original length and it's cross section area was doubled. Find its new resistance.

Answer 1

Answer:

Explanation:

R = ρ* L/A

R ∝ L And R ∝ 1/A

here, length is reduced to 1/5 times so resistance also reduced to 1/5 times

so, resistance is 20/5 Ω = 4 Ω

Again, Area is doubled so resistance get half.

so, New resistance is 4/2Ω = 2Ω

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Amrit

Answer 2

Explanation:

4/2 omega is the right answer that is 2 omega.When we divide 4 by 2 we get 2