Question

question 1 - 15
motors and generators contain similar parts. in both, a wire loop is placed in a magnetic field. which of the following statements about motors and generators is correct?
the wire loop in a motor is mechanically turned producing a current.
in a generator, a current is passed through a wire loop causing it to rotate.
a motor rotates in only one direction producing alternating current.
a generator uses electromagnetic induction to produce a current.

Explanation:

• Option 1: A generator uses electromagnetic induction (Faraday's law) to produce a current. When a coil rotates in a magnetic field, a changing magnetic flux induces an electromotive force (emf) and thus a current. This is correct.
• Option 2: A motor rotates due to the force on a current - carrying conductor in a magnetic field (Fleming's left - hand rule). The current in a motor (in a DC motor, with a commutator) is not in only one direction for producing alternating current. A motor is designed to convert electrical energy to mechanical energy, not to produce alternating current in this way. This is incorrect.
• Option 3: In a generator, it is the rotation of the coil in a magnetic field (causing a change in magnetic flux) that induces a current, not passing a current through a wire loop to cause rotation (that's the principle of a motor). This is incorrect.
• Option 4: In a motor, a current is passed through a wire loop in a magnetic field to produce a force (rotation), not that the wire loop is mechanically turned to produce a current (that's the generator principle). This is incorrect.

Answer:

A. A generator uses electromagnetic induction to produce a current.