JEE Advanced2012PhysicsCurrent ElectricityActual
For the resistance network shown in the figure, choose the correct option(s)
Options
- AThe current through PQ is zero.
- BI ₁=3 ~A
- CThe potential at S is less than that at Q .
- DI ₂=2 ~A
Correct answer
A. The current through PQ is zero.
Step-by-step solution
Resistance of arm P Q and S T becomes ineffective as P & Q and S & T are at the same potential. The equivalent circuit is as shown in the figure. The resistance of the upper arm R₁=2 +2 +2 =6 The resistance of the lower arm R₂=4 +4 +4 =12 Equivalent resistance of the circuit, array l R_ eq = R₁ R₂ R₁+R₂ = (6 )(12 ) 6 +12 =4 I₁= 12 ~V 4 =3 ~A I₂= ( 12 6+12 ) 3=2 ~A I₃=I₁-I₂=1 ~A array Potential difference across A and P , array l V_ A -V_ P =I₂ 2 =(2 A)(2 ) 12 V-V_ P =4 V or V_ P =8 V array Potential difference acro