Question

A) Predict the direction of induced current in the situation described by the following figure


B) Predict the direction of induced current in the situation described by the following figure


C) Predict the direction of induced current in the situation described by the following figure


D) Predict the direction of induced current in the situation described by the following figure


E) Predict the direction of induced current in the situation described by the following figure



F) Predict the direction of induced current in the situation described by the following figure

Answer 1

A) The given figure shows the South Pole of a bar magnet moving towards a closed loop. The direction of the induced current in a closed loop is given by Lenz's law.
Using Lenz's rule, the direction of the induced current will be such that the face of the loop towards the approaching South Pole behaves as South Pole. Because the current induced in solenoid will oppose the approach of magnet and therefore the current at the nearer face should flow clockwise i.e., 𝑞𝑟𝑝𝑞
Final answer: Along qrpq.

B) The given figure shows the South Pole of a bar magnet moving towards the first closed loop (qprq) and North Pole of the bar magnet moving away from the second loop (yzxy).
The direction of the induced current in a closed loop is given by Lenz's law. Using Lenz's rule, the direction of the induced current in the first loop will be such that the face of the loop towards the approaching South Pole behaves as South Pole. Therefore, the direction of the induced current will be along prq.
The direction of the induced current in the second loop will be such that the face of the loop towards the North Pole, which is moving away, behaves as South Pole. Therefore, the direction of the induced current will be along yzx.
Final answer: First Coil -Along prq.
Second Coil- Along yzx.

C) When the tapping key is just closed, the current flows in the coil in clockwise direction when viewed from left and hence magnetic flux linked with it starts increasing.
According to Lenz’s law, the induced current in the adjoining coil should set up in a direction to oppose the growth of magnetic flux linked with the coil.

It will happen so, if the direction of magnetic field produced by the induced current flows in the adjoining coil in anticlockwise direction i.e., the induced current is produced in the direction YZX.
Final answer: Along yzx.

D) Due to change in rheostat setting (resistance decreased), the current in the coil (flowing anticlockwise when viewed from left) and hence magnetic flux linked with it, will start increasing.

According to Lenz’s law, the induced current in the adjoining coil should set up in a direction to oppose the increasing in magnetic flux linked with the coil. Therefore, the induced current in the adjoining coil will flow in clockwise direction when viewed from left i.e., the induced current will flow in the direction zyx.
Final answer: Along zyx.

E) Before releasing the tapping keg, the right end of the core is N-pole and the magnetic field linked with the coil is from left to right. As the tapping keg is released, the magnetic field linked with the coil will start decreasing.
According to Lenz’s Law, the induced current in the adjoining coil should set up in a direction to oppose the decreasing magnetic field i.e., the induced current tries to increase the flux through first coil. It will happen so, if the direction of magnetic field produced by induced current in the adjoining coil is from left to right i.e., the induced current is produced in the direction xry.
Final answer: Along xry.

F) According to Lenz’s law the polarity of induced emf is such that the current produced due to it opposes the change in magnetic flux that produced it in the first place. The current flowing through the straight conductor produces magnetic field in the plane of the coil Therefore, no current will be induced in the coil.
Final answer: No current induced.