Question

please answer the 25 th question of both




I will make him the brainleast

Answer 1

Answer:

25)

The factors are :

i) Using a permanent magnet instead of an electromagnet.

ii) Larger number of coils of wire to be used instead of a single coil.

iii) Inserting a soft iron core into the coil of wire to amplify its magnetic field strength.

                 [OR]

Permanent magnets have fixed field strength. This is not very useful in order to achieve different speeds of fan and mixer-grinder.

Whereas, an electromagnet can change its magnetic field strength by changing the amount of current passing through it. This is exactly what the regulator knob does in the fan and the mixer-grinder.

The electric motor works on the principle - "A current-carrying conductor placed in an external magnetic field experiences a mechanical force."

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NOTE : The force is experienced due to interaction of the magnetic fields of the current-carrying conductor and the external magnetic field.

Direction of the magnetic field can be found out by applying Fleming's Left Hand Rule

Hope it helps!!!