Question

A resistor R and another resistor 2R are connected in a series across a battery. If heat is produced at a rate of 10W in R, then in R it is produced at a rate of: A. 40 W
B. 20 W
C. 10 W
D. 5 W

Answer 1

Answer:

Option B

Solution:

As per the question:

Heat produced at the rate of 10 W  

The resistor R and 2R are in series.

Also, in series, same current, I' passes through each element in the circuit.

Therefore, current is constant in series.

Also,

Power,$P' = I'^{2}R$

When current, I' is constant, then

P' ∝ R

Thus

$\frac{P'}{2R} = \frac{10}{R}$

P' = 20 W