Question

What type of energy transformation takes place in a dynamo?
A. Electrical to heat energy.
B. Mechanical to heat energy.
C. Mechanical to electric energy.
D. Heat to mechanical energy.

Answer 1

Hint: We should have the idea that a dynamo works on the principle of law of conservation of energy to solve this question. The term transformation of energy means the transfer of one form of energy to a different form. We must know that a dynamo is used as electrical generators for delivering power.

Complete answer:
We know that according to the first law of thermodynamics or the law of conservation of energy, energy can neither be created nor be destroyed but it can only be converted from one form into another form.

In the case of a dynamo, it converts mechanical energy given into electrical energy. So, we can call a dynamo an electrical generator that produces direct current with use of a commutator. If we look at the working of a dynamo, it is made up of stationary magnets (stator) which creates a powerful magnetic field, and rotating magnet (rotor) which distorts and cuts through the magnetic lines of flux of the stator. This cutting through the lines will create variation in magnetic flux and hence it produces electricity. This rotation of magnet is done by mechanical means.

In the given diagram, the two fixed magnets act as stator and the spinning coil acts as rotor.
Therefore, we can conclude that a dynamo is an electrical generator which converts mechanical energy into electric energy.

So, the correct answer is “Option C”.

Note:
For solving these types of questions, we must know the definition of energy which is termed as the capacity to work. Also the fact that the total energy for a process always remains constant. We must know that dynamos are used in power stations to create electricity for industrial and domestic purposes in ancient times which were replaced by alternators nowadays. They were still used for low power electrical applications.