Question

A $2\text{W}$ carbon resistor is color coded with green, black, red and brown respectively. The maximum current which can be passed through this resistor is

• A. $0.4\text{mA}$
• B. $63\text{mA}$
• C. $100\text{mA}$
• D. $20\text{mA}$

Answer 1

The correct option is D $20\text{mA}$

Given:
Power $=2\text{W}$
carbon resistor color coded -green, black, red and brown
We have resistance table-


Resistance, $R=AB\times C\pm D$
As per the colour coding given in question we have resistance value,
$R=50\times {10}^2\Omega$

Now using formula, power,

$P=i^{2}R$

$\Rightarrow i=\sqrt{\frac{P}{R}}=\sqrt{\frac{2}{50\times {10}^2}}=20\text{mA}$


Hence, option $\left(A\right)$ is correct.