Physics, asked by suresh6357, 1 year ago

If a 9 ohm wire is tripled around itself. What will be change in resistance

Answers

Answered by tejasgupta
2

Answer:

R' = 1 Ohm

Explanation:

Given resistance (R) = 9 Ohm

Initial Length = L

Initial Area of cross section = A

Let resistivity = x

Then, from R = xL/A, 9 = xL/A - (eqn.1)

Now,

New length = l = L/3

New Area of cross section = a = 3A

Resistivity remains the same, ie x.

Let new resistance be R'.

From R = xL/A, R' = x(L/3)(1/3A)

or, R' = xL/9A

or, 9R' = xL/A - (eqn.2)

From eqn.1 and eqn.2, we get

9 = 9R'

or, R' = 9/9 = 1 Ohm

Thus, new resistance = R' = 1 Ohm.

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