Saved Bookmarks
| 1. |
State the causes of induced current and explain them on the basis of Lena’s law. |
|
Answer» According to Lena’s law, the direction of the induced emf or current is such as to oppose the change that produces it. The change that induces a current may be (i) the motion of a conductor in a magnetic field OR (ii) the change of the magnetic flux through a stationary circuit. In the first case, the direction of induced emf in the moving conductor Is such that the direction of the side-thrust exerted on the conductor by the magnetic field is opposite in direction to its motion. The motion of the conductor is, therefore, opposed. In the second case, the induced current sets up a magnetic field of its own which within the area bounded by the circuit is (a) opposite to the original magnetic field if this field is increasing, but (b) is in the same direction as the original field, if the field is decreasing. Thus, it is the change in magnetic flux through the circuit (not the flux itself) which is opposed by the induced current. |
|