Question

a conductor offers a resistance of 30 ohm what will be its resistance if it is doubled on itself​

Answer 1

Answer:

120 ohm

Explanation:

The resistance, R, of a wire of length l is given by,

R= ρl/A

Now if the wire is stretched keeping the volume intact then:R=ρl²/V. (V/l=A)

Now R∝l²

According to the question, we get,

R2/R1=(l2)²/(l1)²

R2=30×4. (l2=2l1 )

⇒R =120Ω