Question

A and B are two identical rods of internal resistance $r=1\Omega .$ If $R=2\Omega ,V_A=4m/s,V_B=3m/s$, length of rods is 1 m, then current in R is (Magnetic field is 2T)

• A. $1A$
• B. $0.4A$
• C. $0.6A$
• D. $0.8A$

Answer 1

The correct option is B $0.4A$


The voltage in induced in the left rod is $BVL=2\times 4\times 1=8V$. The bottom part of the rod is at higher potential.

The voltage in induced in the rightside rod is $BVL=2\times 3\times 1=6V$. The top part of the rod is at higher potential.

By K.V.L,
$8=i+2i^1$ ...(1)
$6=(1-i^1)-2i^1$
$\Rightarrow 6=i-3i^1$ ...(2)
By (1) & (2)
$i^1=0.4A$