Question

In the given circuit, the current through Zener diode is $\frac{5k}{3}\text{mA}$. The value of $k$ is ___

• A. $1$
• B. $3$
• C. $4$
• D. $2$

Answer 1

The correct option is D $2$

The voltage across $500\text{ohm}$ resistor is, $V_{R_1}=15-10=5\text{V}.$

The current through it,

$I=\frac{5}{500}=10\text{mA}$

The current through $1500\text{ohm}$ resistor is,

$I_{R_2}=\frac{10}{1500}=\frac{20}{3}\text{mA}$

So, the current through the Zener diode is

$I_Z=10-\frac{20}{3}=\frac{10}{3}\text{mA}$

Given, $I_Z=\frac{5k}{3}\text{mA}$

$\therefore k=2$

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