The reverse breakdown voltage of a Zener diode is 5.6 V in the given circuit. The current Iz through the Zener is:
(1)
P.D. across 800Ω resistors=5.6 V
So, I800Ω=5.6800 A=7 mA
Now, P.D. across 200Ω resistors
=9-5.6 V=3.4 V
So, I200Ω=9-5.6200=17 mA
So, current through zener diode =IZ=17-7=10 mA