Question

A wire of resistance 10 ohm is doubled up by streching. Calculate new resistance
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Answer 1

Given,

• Resistance = 10 Ω

We know the equation :

$\boxed{\bold{\sf{R = \dfrac{\rho \times l}{A}}}}$

Where,

• R = Resistance
• ρ = Resistivity
• l = Length
• A = Area of cross section

If the resistance get doubled,

• Length of the wire gets halved.
• Area of cross section gets doubled.

$\bold{\sf{\implies R = \dfrac{\rho \times \frac{l}{2}}{2A}}}$

$\bold{\sf{\implies R = \dfrac{\rho \times l}{4A}}}$

In the question, it is given that :

$\bold{\sf {\dfrac{\rho \times l}{A}=10}}$

Therefore:

$\sf{\implies New \ Resistance = \dfrac{10}{4}}$

$\sf{\implies New \ Resistance = 2.5 \ {\Omega}}$

$\huge{\boxed{\bold{\sf{\therefore New \ Resistance = 2.5 \ {\Omega}}}}}$

Answer 2

Answer:

the answer is 2.5 Omega

Explanation:

the answer is 2.5 Omega