GEOLOGY

EARTH SCIENCE

MAGNETISM

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
In a simple electric generator, a conducting loop of wire is placed in a magnetic field. The loop of wire is then rotated. Why is it necessary for the wire to be rotated?
A
Its motion when it moves upward changes gravity into magnetism
B
Its motion through the magnetic field creates a current in the wire.
C
Its motion removes the magnetic field by using up the magnetic energy.
D
Its motion through the air transforms heat into magnetism
Explanation: 

Detailed explanation-1: -Explanation: A current traveling through a wire will produce a magnetic field. If a wire is rotated within a magnetic field, a current will be produced. It is necessary for the wire to be rotated because its motion through the magnetic field creates a current in the wire.

Detailed explanation-2: -If a coil of wire is placed in a changing magnetic field, a current will be induced in the wire. This current flows because something is producing an electric field that forces the charges around the wire.

Detailed explanation-3: -When the wired loop rotates, then the flux passing through the loop starts to decrease. When it becomes parallel to the magnetic field, then the flux becomes zero and then it starts to increase. Here, the direction of the induced emf will always remain the same.

Detailed explanation-4: -The magnet creates an electromotive force, which causes the electrons in the wire to move, inducing an electric current. The rotation of the magnet or wire loop alternates between “pushing” and “pulling” the electrons due to the magnets polarity.

Detailed explanation-5: -passing through the loop since B is perpendicular to the area of the loop. Since the velocity of the loop and the magnetic field are CONSTANT, however, this flux DOES NOT CHANGE IN TIME. Therefore, there is NO emf induced in the loop; NO current will flow!!

There is 1 question to complete.