Question

The value of power dissipated across the zener diode $\left(V_z=15V\right)$ connected in the circuit as shown in the figure is $x\times 10^{-1}$ watt.

The value of $x$, to the nearest integer, is ______.

Answer 1

Answer: 5

Voltage across $R_S=22-15=7V$
Current through $R_S=I=\frac{7}{35}=\frac{1}{5}A$
Current through $90\Omega =I_2=\frac{15}{90}=\frac{1}{6}A$
Current through $=\frac{1}{5}-\frac{1}{6}=\frac{1}{30}A$
Power through zener diode
$P=VI$
$P=15\times \frac{1}{30}=0.5watt$
$P=5\times 10^{-1}$ watt