Question

Two resistance $R_{1}$ and $R_{2}$ when connected in series consume power $25W.$ When connected in parallel, they consume $100W.$ What is the ratio of the power of each?

• A. $1/4$
• B. $1/3$
• C. $1/2$
• D. $1$

Answer 1

Answer: (D)

Let $W_{1}$ and $W_{2}$ be the power of two resistances.
Then, $W_{1}+W_{2}=100$ and $\frac{W_{1} W_{2}}{ W_{1} + W_{2}}=25$
$\Rightarrow W_{1}W_{2}=2500$
On solving, we get $W_{1}=W_{2}=50.$
$\therefore W_{1}/W_{2}=1$