Question

Lenz's law of electromagnetic induction corresponds to the

• A. law of conservation of charge
• B. law of conservation of energy
• C. law of conservation of momentum
• D. law of conservation of angular momentum

Answer 1

The correct option is B

law of conservation of energy

The explanation for the correct option

In the case of option B,

1. Lenz's Law states that, when we induce a current in a wire via a changing magnetic field, the current flows through the wire in such a direction so that its magnetic field opposes the change that produced the current.
2. When a current is induced by moving a wire through a magnetic field, is that we are converting mechanical energy (the energy of the wire's motion) into electrical energy (the energy carried by the induced current).
3. Lenz's Law ensures that the mechanical energy of the wire is reduced by the same amount of energy gained by the current. It does this by exerting a force on the wire opposing the wire's motion. This causes the wire to lose mechanical energy, it must do work against the induced magnetic field to generate current. Thus energy is conserved.

The explanation for the incorrect options

In the case of option A,

1. Lenz's law is based on only the law of conservation of energy.
2. As we know the induced current opposes the electromotive force, so there will be work done against this opposing force.
3. If the total charge will be conserved, no induced current will be there.
4. Hence, option A is incorrect.

In the case of option C,

1. Lenz's law is based on only the law of conservation of energy.
2. As we know the induced current opposes the electromotive force, so there will be work done against this opposing force.
3. There is nothing conservation about the momentum, which is the product of the mass and velocity.
4. If momentum will be conserved no external force will be there.
5. Hence, option C is incorrect.

In the case of option D,

1. Lenz's law is based on only the law of conservation of energy.
2. As we know the induced current opposes the electromotive force, so there will be work done against this opposing force.
3. There is nothing conservation about the angular momentum, which is the product of the moment of inertia and angular velocity.
4. If angular momentum will be conserved no torque will be there.
5. Thus, option D is incorrect.

Hence, option B is the correct answer.