Physics, asked by goki15, 1 year ago

The resistance of a wire is 20 ohm .what will be new resistance, if it is stretched uniformly 8 times it's original length?​

Answers

Answered by awaisanwar492
5

Answer:

R' = 160 ohm

Explanation:

R = rho L / A

R will also become 8 times

so R' = 160 ohm

Answered by agis
13

Answer:

The new resistance will be 1280 ohm.

Explanation:

The resistance of the wire is given as

R=\rho\frac{L}{A}

Here,   L is the length of the wire, A is the area of the wire and \rho is the resistivity of the wire.

Now new length of the wire, l = 8L.

If a   be the new cross-sectional area, then

a l = AL  (as volume of the wire remain constant)

a (8 x L) = AL

a =  A/8.

Therefore, new resistance of the wire

r=\rho\frac{l}{a}

Or,

r=\rho\frac{8L}{A/8}=64R

Given R = 20 ohm.

So,

r=64\times20

r = 1280 ohm.

Thus, the new resistance will be 1280 ohm.

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