Question : A wire of uniform cross section and resistance 12 Ω is bent in the shape of a circle as shown. A resistance of 10 Ω is connected to diametrically opposite ends C and D. A battery of EMF 8 volt is connected between A and B. Determine the current flowing through the arm AD.
Doubt by Ridhi
CBSE Sample Question Paper 2023-2024
Solution : Total resistance of wire (R) = 12 Ω
RAD=RBD=[60°/360°]×12
=12/6
= 2Ω
RAC=RBC=[120°/360°]×12
= 2Ω
RAC=RBC=[120°/360°]×12
=12/3
=4 Ω
=4 Ω
Here the equivalent figure will be a balanced wheat stone bridge. Hence, no current will flow through 10Ω resistance.
The equivalent circuit will look like the one as shown below
Current through AD (IAD) = Current through ADB (IADB)
IAD=IADB=V/RADB
=8/4
= 2 A
Hence, the current flowing through the arm AD is 2 A.