Question

a wire has resistance 15 ohm if it's cross section area is tripled but length is kept the same, how would it affect the resistance of the wire?​

Answer 1

Answer:

Hope it helps you Anushya....

Answer 2

Given:

A wire has resistance 15 ohm.

To find:

If it's cross section area is tripled but length is kept the same, how would it affect the resistance of the wire?

Calculation:

Let area be A and length be L .

$\therefore \: R = \rho \times \dfrac{L}{A} = 15 \: ohm$

Now, as per the question,

• Length remains constant.

• Area of cross section is made triple.

$\therefore \: R2 = \rho \times \dfrac{L}{3A}$

$\implies \: R2 = \dfrac{1}{3} \times \bigg( \rho \times \dfrac{L}{A} \bigg)$

$\implies \: R2 = \dfrac{1}{3} \times \bigg( 15 \bigg)$

$\implies \: R2 = 5 \: ohm$

So, new resistance of wire is 5 ohm , i.e. the resistance becomes ⅓rd of initial resistance.