Lenz's law of electromagnet states that

• A.the induced charge is constant for a fixed change of force
• B.a force is exerted on a current-carrying conductor in a magnetic field
• C.the magnitude of the induced e.m.f in a circuit is proportional to the rate of change of the number of lines of force linking the circuit
• D.the induced current in a conductor is in such a direction as to oppose the change producing it
• E.e.m.f. is induced in a circuit whenever there is a change in the magnetic flux linked with the circuit