Question

The commercial motors use

• A. an electromagnet in place of permanent magnet
• B. large number of turns of the conducting wire in the currentcarrying coil
• C. a soft iron core on which the coil is wound
• D. all

Answer 1

The correct option is D all

In commercial motors,

i) Large torque is required to transfer, thus high strength magnet is required thus electromagnets are used.

ii) Torque $\propto$ number of turns

Large number of turns are used.

iii) Soft iron core has practically the maximum permittivity thus used.