Question

using Kirchhoff's rule determine the value of unknown resistance R in the circuit shown in figure so that no current flows to 4 ohm resistance also find the potential difference between a and d​

Answer 1

Answer:

Applying Kirchhoff's second law in closed mesh AFEBA ,

9−6=I×1+I×1+4×0=0 (current in 4Ω is given zero)

or 3=2I

or I=3/2=1.5A

now in closed mesh AFEDCBA ,

9−3=I(1+1)+IR

or 6=1.5×2+1.5R

or 6=3+1.5R

or R=3/1.5=2Ω

now from point A to point D , (applying Kirchhoff's law for linear part AFED)

V

A

−I(1+1)=V

D

or V

A

−V

D

=1.5×2=3V