Question

efficient when the train is moving slowly. The system needs an ordinary friction-based brake to bring the train to a full stop. Explain why the magnetic brake is not very efficient when the train is moving slowly. The slower the train is moving, the greater are the changes of the magnetic flux, thus the eddy currents become stronger. The slower the train is moving, the less are the changes of the magnetic flux, thus the eddy currents become weaker. The slower the train is moving, the less are the changes of the magnetic flux, thus the eddy currents become stronger. The slower the train is moving, the greater are the changes of the magnetic flux, thus the eddy currents become weaker.

Answer 1

Answer:

The slower the train is moving, the less are the changes of the magnetic flux, thus the eddy currents become weaker.

Explanation:

A magnetic brakes is not a very efficient way of braking when a train is moving slowly because at low speeds, the changes in the magnetic flux are very less and so it causes the eddy current to become weaker.

Let us find the drag force which is proportional to the velocity of two conducting plates.

The EMF that is induced in the eddy currents are : $E=v(B \times L)$

The force which is due to the induced magnetic field is, $F=l(L \times B)$

Therefore, $F=\frac{E}{R} \times (L \times B)$

                 $F=\frac{v(B \times L)}{R} \times (L \times B)$

Here, force is directly proportional to the velocity of the two conducting plates.

Therefore, we can say that when the speed of the train is low, the magnetic flux changes are less and thus the eddy currents are weaker.