Question

source voltage= 40V

series resistance = 200 ohm

zener voltage= 15V

Answer 1

$V_{In}=40V,$ $R_s=200\Omega$

$V_z=15V$

and let $R_L=500\Omega$

$V_{across} \>R_s=40-15$

$=25V$

$I_s=\frac{25}{200}=125mA$

$I_L=\frac{15}{500}=30mA$

$\implies\>I_z=125-30mA$

$=95mA$