Question

A 8 resistance wire is streched to doubled its length.then find new resistance of wire

Answer 1

Since we know that,

R = p × l/A

• where, p = proportionality constant (rho), resistivity.
• L stands for length of conductor.
• A stands for cross section area of conductor.

So, let orginal resistance be R and new one be R'.

⇒ R = p × l/A = 8 ohms

When the length of Resistor is doubled then, area will decrease by half automatically due to concept that nothing has been added in a wire.

⇒ R' = p × 2l/(A/2)

⇒ R' = p × 4l/A

⇒ R' = 4 × (p × l/A)

⇒ R' = 4 × R = 4 × 8 ohms

⇒ R' = 32 ohms

→ Answer : 32 Ω