The correct answer is: C. Both (A) and (B)
A DC generator is a device that converts mechanical energy into electrical energy by using a rotating magnetic field. The magnetic field is produced by either an electromagnet or a permanent magnet.
In an electromagnet, a current is passed through a coil of wire to create a magnetic field. The magnetic field is stronger when more current is passed through the coil.
In a permanent magnet, the magnetic field is created by the alignment of magnetic domains in the material. The magnetic field is permanent and does not require an external current to be maintained.
In a DC generator, the rotating magnetic field is used to induce an electric current in a stationary coil of wire. The direction of the induced current is determined by the right-hand rule.
The right-hand rule states that if you point your right thumb in the direction of the magnetic field, your fingers will curl in the direction of the induced current.
The amount of current that is induced in the coil is proportional to the strength of the magnetic field, the speed of rotation of the magnetic field, and the number of turns in the coil.
The DC generator is a very important device that is used in a variety of applications, including power generation, motor drives, and welding.