Parallel Circuits - Technical MCQs

Q1:

Which component is open?
 
mcq4_1011_1.gif

A R1

B R2

C R3

D R4

ANS:A - R1

Here we have a total current of the 21m amp,
Current across R1is.
I1=v/R1=12/1*10^3=12m amp

Current across R2 is;
I2=v/R2=12/2*10^3=6m amp,
Remaining current is 3m amp.

Then current across R4 is,
I3=v/R4=12/2*10^3=3m amp,
Hence resistor R3 is open circuit.