As shown in the figure, $$P$$ and $$Q$$ are two coaxial conducting loops separated by some distance. When the switch $$S$$ is closed, a clockwise current $${I_P}$$ flows in $$P$$ (as seen by $$E$$) and an induced current $${I_{{Q_1}}}$$ flows in $$Q.$$ The switch remains closed for a long time. When $$S$$ is opened, a current $${I_{{Q_2}}}$$ flows in $$Q.$$ Then the direction $${I_{{Q_1}}}$$ and $${I_{{Q_2}}}$$ (as seen by $$E$$) are
A.
respectively clockwise and anti-clockwise
B.
both clockwise
C.
both anti-clockwise
D.
respectively anti-clockwise and clockwise
Answer :
respectively anti-clockwise and clockwise
Solution :
When switch $$S$$ is closed, a magnetic field is set-up in the space around $$P.$$ The field lines threading $$Q$$ increases in the direction from right to left. According to Lenz's law, $${I_{{Q_1}}}$$ will flow so as to oppose the cause and flow in anticlockwise direction as seen by $$E.$$ Reverse is the case when $$S$$ is opened. $${I_{{Q_2}}}$$ will be clockwise.
Releted MCQ Question on Electrostatics and Magnetism >> Electromagnetic Induction
Releted Question 1
A thin circular ring of area $$A$$ is held perpendicular to a
uniform magnetic field of induction $$B.$$ $$A$$ small cut is made in the ring and a galvanometer is connected across the ends such that the total resistance of the circuit is $$R.$$ When the ring is suddenly squeezed to zero area, the charge flowing through the galvanometer is
A thin semi-circular conducting ring of radius $$R$$ is falling with its plane vertical in horizontal magnetic induction $$\overrightarrow B .$$ At the position $$MNQ$$ the speed of the ring is $$v,$$ and the potential difference developed across the ring is
A.
zero
B.
$$\frac{{Bv\pi {R^2}}}{2}$$ and $$M$$ is at higher potential
Two identical circular loops of metal wire are lying on a table without touching each other. Loop-$$A$$ carries a current which increases with time. In response, the loop-$$B$$
A coil of inductance $$8.4 mH$$ and resistance $$6\,\Omega $$ is connected to a $$12 V$$ battery. The current in the coil is $$1.0 A$$ at approximately the time