Lenz's Law

Q. A conducting ring is placed around the core of an electromagnet as shown in fig. When key K is pressed, the ring: (Consider the ring is light weight)

1. Is attracted towards the electromagnet.
2. Jumps out of the core.
3. Revolves around the core.
4. Remains stationary.

Q. Two identical coaxial circular loops carry current i each circulating in the clockwise direction. If the loops are approaching each other, then:

1. The net current in each loop increases.
2. The net current in one loop increases but it decreases in the other.
3. The net current in each loop remains the same.
4. The net current in each loop decreases.

Q. A magnet NS is suspended from a spring and while it oscillates, the magnet moves in and out of the coil C. The coil is connected to a galvanometer G. Then as the magnet oscillates,

1. G shows deflection on one side
2. G shows no deflection.
3. G shows deflection to the left and right but the amplitude steadily decreases.
4. G shows deflection to the left and right with constant amplitude

Q. An electron moves along the line AB, which lies in the same plane as a circular loop of conducting wires as shown in the diagram. What will be the direction of current induced if any, in the loop

1. The current will be clockwise.
2. No current will be induced.
3. The current will be anticlockwise.
4. The current will change direction as the electron passes by.

Q. A coil having n turns and resistance R $\Omega$ is connected with a galvanometer of resistance 4R$\Omega$ . This combination is moved in time t seconds from a magnetic field $W_1$ weber to $W_2$ weber. The induced current in the circuit is

1. 
2. 
3. 
4. 

Q. An electron moves on a straight line path 'XY' as shown. The 'abcd' is a coil adjacent to the path of electron. What will be the direction of current, if any, induced in the coil?

1. No current induced
2. adcb
3. abcd
4. The current will reverse its direction as the electron goes past the coil

Q. The direction of induced current or the polarity of induced emf can be found by

1. Amber’s law
2. Kirchoff's law
3. Lenz’s law
4. Lorentz’s law

Q. A bar magnet is thrown along the axis of a ring with speed $v_0$. After sometime, speed of magnet is $v$, then

1. Information is incomplete
2. $v<v_0$
3. $v>v_0$
4. $v=v_0$

Q. A small magnet $M$ is allowed to fall through a fixed horizontal conducting ring $R$. Let $g$ be the acceleration due to gravity. The acceleration of $M$ will be

1. $<g$ when it is above R and moving toward R.
2. $>g$ when it is above R and moving toward R.
3. $<g$ when it is below R and moving away from R.
4. $>g$ when it is below R and moving away from R.

Q. A wire is bent to form the double loop as shown in the figure. There is a uniform magnetic field directed into the plane of the loop. If the magnitude of this field is decreasing, the current will flow from

1. B to A and D to C
2. A to B and C to D
3. A to B and D to C
4. B to A and C to D