question_answer 30)

  A solenoid is connected to a battery so that a steady current flows through it. If an iron core is inserted into the solenoid, will the current increase or decrease? Explain.

Answer:

                  The current will decrease. This is because on inserting an iron core in the solenoid, magnetic field and hence magnetic flux linked with the solenoid increases. As per Lenz's law, the emf induced in the solenoid will oppose this increase, which can be achieved by a decrease in current.