Electromagnetic brakes work on the principle of electromagnetic induction. If a metallic disc or a coil is rotating in a uniform magnetic field, it will experience a torque due to induced currents set up in the disc. According to Lenz's law, induced current is in a direction so as to oppose the rotation. Hence a retarding torque is produced. The rotating wheel of a vehicle is connected to a coil placed in a uniform emf is used to charge a battery. Thus kinetic enery of wheel is stored as chemical energy. The drawback of electromagnetic brake is that induced current or retarding torque is directly proportional to speed of rotation. The speed, therefore, decays exponentially and vehicle will take a long time to stop. Thus, mechanical brakes are used simultaneously.
The advantage of electromagnetic brakes is that

Options

A. It is more effective as instant brakes are applied
B. It is more economical as it saves energy
C. It is easier and simple to design
D. It is based on conservation of energy

Answer

B