In the circuit Fig., what is the range over which the load resistance can be varied?

Options

A. `298.6Omegale R_(L) lt oo`
B. `303.7megale R_(L) lt oo` only
C. `408.2megale R_(L) lt oo` only
D. `428.6megale R_(L) lt oo` only

Answer

D

Explanation

Pot. Diff. across `100 Omega=15-12=3V`
current through `100 Omega`
`I=(3V)/(100Omega)=0.03 A=30 mA`
Current through `R_(L)=30-2=28 mA`
Pot. Diff. across `:. R_(L)=12 V`
`R_(L)=(12V)/(28xx10^(-3)Omega)=428.6 Omega` If `R_(L) =oo`, then voltage across zener diode will be more than 12 V and it will not work properly.