Question

A Zener diode of Zener break-down voltage $10V$ is connected as shown in the figure. Current through Zener diode is

• A. $4mA$
• B. $0.6mA$
• C. $6mA$
• D. Zero

Answer 1

Answer: (D)

If we consider break down in Zener diode, then potential across $R_3$ will be $10V$ and $R_1$ will be $2V$ .
So current in $R_3$ will be $i_3=\frac{10}{1500}=\frac{2}{300}A$
and current in $R_1$ will be $i_1=\frac{2}{500}A$
$\Rightarrow i_1<i_3$ , which is not possible
$\Rightarrow$ The potential difference across the Zener diode does not reach to break down voltage. So no current will flow through the reverse-biased Zener diode.