JEE Main 2015 · 11 Apr · Shift 1 · Physics Q18

PhysicsSingle correct+4 / -1Question 18 of 90

The value of the resistor, $R_S$ , needed in the dc voltage regulator circuit shown here, equals :

(V_i-V_L)/nI_L

(V_i+V_L)/nI_L

(V_i-V_L)/(n+1)I_L

(V_i+V_L)/(n+1)I_L

Answer and worked solution

Official answer: C

$R_S$ carries the Zener current plus the load current, $(n+1)I_L$ , and drops $V_i-V_L$ :
$R_S=\frac{V_i-V_L}{(n+1)I_L}.$

JEE Main 2015 · 11 Apr · Shift 1, Physics question 18