Question

Which form of energy is converted into which form of energy by a dynamo?
${\text{A}}{\text{.}}$ Mechanical energy into sound energy
${\text{B}}{\text{.}}$ Mechanical energy into electrical energy
${\text{C}}{\text{.}}$ Electrical energy into mechanical energy
${\text{D}}{\text{.}}$ Electrical energy into sound energy

Answer 1

Hint- Here, we will be discussing the need for devices which convert one form of energy into another. Then, we will be mentioning all the devices which are used for the conversion of the forms of energies mentioned in the options of the problem.

Complete Step-by-Step solution:
Various devices are used to convert one form of energy into another form of energy. This conversion of energy is needed in order to get the form of energy which is required at the moment. A device is selected which is able to convert the available form of energy into the required form of energy for its utilization with minimal energy losses occurring and getting maximum efficiency.
A loudspeaker is a device which is used to convert the mechanical form of energy into sound energy. The part of the loudspeaker that converts electrical into mechanical energy is frequently called the motor, or voice coil. The motor vibrates a diaphragm that in turn vibrates the air in immediate contact with it, producing a sound wave corresponding to the pattern of the original speech or music signal.
An electrical generator that creates direct current using a commutator is a dynamo. A dynamo is a device which converts mechanical energy (or power) into electrical energy (i.e., gives direct current from the produced electrical power). These were the first electrical generators that were used to deliver power for industry. Based on the principle of these devices, many electric power conversion devices were developed later including the alternating-current alternator, the electric motor, and the rotary converter.
A device which converts electrical energy into mechanical energy is called an electrical motor. These devices are based on the magnetic and electric field interaction as their working principle.
A generator also converts mechanical energy into electrical energy, while a motor converts electrical energy into mechanical energy. Both the devices work because of electromagnetic induction, which is when a voltage is induced by a changing magnetic field.
A loudspeaker is a device which is used for the conversion of electrical energy into sound energy as discussed above also.
Therefore, option B is correct.

Note- A simple dynamo with a coil made from conducting wire which is placed between the North and the South poles of two permanent magnets. No voltage is induced when the coil is stationary. As the coil rotates, there is a change in the magnetic field which induces a voltage within the coil.