Question

The figure shows a square loop $L$ of side $5\, cm$ which is connected to a network of resistances. The whole setup is moving towards right with a constant speed of $1\, cms^{-1}$. At some instant, a part of $L$ is in a uniform magnetic field of $1T$, perpendicular to the plane of the loop. If the resistance of $L$ is $1.7\, \Omega$ , the current in the loop at that instant will be close to :

• A. $115\, \mu A$
• B. $170 \, \mu A$
• C. $60\, \mu A$
• D. $150\, \mu A$

Answer 1

Answer: (B)

$170 \, \mu A$

Answer 2

Since it is a balanced wheatstone bridge, its equivalent resistance $= \frac{4}{3} \Omega$ $\varepsilon = B \ell v = 5 \times 10^{-4} V$ So total resistance $R = \frac{4}{3} + 1.7 \approx 3\Omega$ $\therefore \; i \frac{\varepsilon}{R} \approx 166 \mu A \; \approx \; 170 \mu A$