Question

A metallic wire of resistance 20 ohm stretched until its length is doubled its resistance is

Answer 1

Since R=rho×L/A
We can see that R is directly proportional to L
Or if we substitute Las 2L (cause length is doubled)
We get...
R=rho×(2L)/A
R=2×rho×L/A
So R will be doubled...and now the value of R will be 2×20=40ohm



Hope this helps

Answer 2

Answer:

80 ohm

Explanation:

hope it helps you

this is the correct