Question

In an electrical circuit, two resistors of $2\Omega$ and $4\Omega$ are connected in series to $6\text{V}$ battery. The heat dissipated by the $4\Omega$ resistor in $5\text{s}$ will be -

• A. $50\text{J}$
• B. $30\text{J}$
• C. $20\text{J}$
• D. $40\text{J}$

Answer 1

The correct option is C $20\text{J}$

Given circuit is,


Current in the circuit,

$i=\frac{6}{4+2}=1\text{A}$

Now, the heat dissipated by the $4\Omega$ resistor in $5\text{s}$ will be,

$H=i^{2}Rt=1^2\times 4\times 5=20\text{J}$

Hence, option $\left(C\right)$ is the correct answer.