Question

Two conductors made of the same material are connected across a common potential difference. Conductor A has twice the diameter and twice the length of conductor B. The power delivered to the two conductors $P_{A}$ and $P_{B}$ respectively is such that $P_{A}/P_{B}$ equals to

• A. 0.5
• B. 1.0
• C. 1.5
• D. 2.0

Answer 1

Answer: (D)

2.0

Answer 2

$R = \rho\frac{l}{A}$and$P \propto \frac{1}{R}$⇒$P \propto \frac{A}{l}$⇒$P \propto \frac{d^{2}}{l}$⇒ $P_{A} = 2P_{B}$