Question

Given below are some devices. Identify the one that doesn’t work on the principle of electromagnetic induction. Also mention the principle on which it works.

A.)Dynamo
B.)Loud speaker
C.)Microphone
D.)Transformer

Answer 1

Hint: The development of an electromotive force (i.e. voltage) through a conductor by a shifting magnet field or change of flux through the conductor is electromagnetic or magnetic induction.

Complete answer:
The induced field is normally defined by Lenz 'Law. The law of Faraday was subsequently extended to become one of the four Maxwell equations in electromagnetism theory. Several systems, including electric components such as inducers, transformers, electrical inducers and tools including motors or generators have been defined for electrical induction.

(i)Dynamo: by spinning a wire inside a magnetic field that is based on the operating theory of electromagnetic induction, Dynamos generates electrical current.

(ii)Loud speaker: based on the motor concept

(iii)Microphone: also based on the electromagnetic induction theory.

(iv)Transformer: Transformer, which plays a significant function, is based on the theory of electromagnetic induction.

Hence, option B doesn’t work on the principle of electromagnetic induction. It rather works on the principle of motor.

Additional Information:
An electric motor is an electric machine which transforms power into mechanical energy. Many electric motors operate as a torque appliqué to the engine shaft by way of the contact between the magnetic field of the motor and the electric current in a wire winding. Electric motors may be powered by direct current (DC) sources like batteries, motor vehicles or rectification systems or alternating current (AC) sources, like energy grids, inverters or electrical generators. An electrical generator is physically identical to the electric motor, but works through a reverse power stream that transforms mechanical energy to electricity.

Note: Automotive motors, blowers and generators, hand machines, home equipment, mechanical control devices and disks are fitted with electrical engines. In electric watches, tiny motors can be mounted. Electric motors may be used in reverse as generators to restore electricity, otherwise lost as heat and friction in some applications such as in regenerative braking with traction engines.