Question

A WIRE OF GIVEN MATERIAL HAVING LENGTH L AND AREA OF CROSS SECTION A HAS A RESISTANCE 10 OHM . WHAT WOULD BE RESISTANCE OF ANOTHER WIRE OF THE SAME MATERIAL HAVING LENGTH L/4 AND AREA OF CROSS SECTION 2.5 A

Answer 1

Explanation:

$R = p \frac{l}{a}$

• Resistance is directly proportional to length of wire
• Resistance is inversely proportional to area

$R \: \infty \: \frac{l}{a}$

$\frac{R1}{R2} = \frac{ \frac{l1}{a1} }{ \frac{l2}{a2} }$

$\frac{10}{R2} = \frac{ \frac{l}{a} }{ \frac{l}{4 \times 2.5a} }$

$\frac{10}{R2} = 10$

$R2 = 1 \: ohm$