Question

A resistance $R$ whose value is varied from $1 \, \Omega \, $ to $5 \, \Omega $ is connected to a cell of internal resistance $3 \, \Omega $ . The power consumed by $R$

• A. increases continuously
• B. decreases continuously
• C. first decreases then increases
• D. first increases then decreases

Answer 1

Answer: (D)

$P=\left(\frac{E}{R + 3}\right)^{2}R$
$\frac{dP}{dR}=0 \, at \, R=3\Omega $ so power is maximum at
Therefore increase continuously till $R=3\Omega $ and then decreases