Question

A thick wire of resistance is 10 ohm is stretched to form a thin wire.such that its length becomes three times. What will be new resistance

Answer 1

Answer:

Given data:

$R_{1}$ = 10 Ω

Since given that wire is stretched i.e.        $L_{2}$ = 3 $L_{1}$  

As for stretched wire, we have

R = $n^{2}$ R

Since   n = 3

So

R = $3^{2}$ (10)

  = 9 (10) = 90 Ω

Explanation:

Answer 2

Answer:- 90 ohms

Explanation:-

Initial length of wire ,L1 = l

Final length of wire L2= 3l

Initial resistance of wire is R1= 10 ohms (given)

Final resistance = ? (R2)

W.K.T,

R Is directly proportional to l^2

=> R2/R1=(L2/L1)^2 = (3l/l)^2 = 9

R2 = 9R1

=> 9*10 = 90 ohms.