Question

Quantity that remains unchanged in a transformer is
A) Voltage
B) Current
C) Frequency
D) None of the above

Answer 1

Hint:A transformer is a passive electrical device that transfers electrical energy from one circuit to another through the process of electromagnetic induction. It is most commonly used to increase or decrease voltage levels between circuits. Check the working principle of the transformer and accordingly check which of the given quantity remains unchanged.

Complete step-by-step solution: We know that a transformer is a that transfers energy from one device to another. It is commonly used to increase or decrease the voltage supply without changing the frequency of AC between circuits. Transformers work on the basic principles of electromagnetic induction and mutual induction.
The voltage between two devices can increase and decrease but the frequency remains constant.
Therefore, option C is the correct option.

Additional details: Commonly used transformers are of two types based on their voltage:
Step-up Transformer: These types of transformers are used between the power generator and the power grid. The secondary output voltage is higher than the input voltage.
Step down Transformer: These transformers are used to convert high voltage primary supply to low voltage secondary output hence the name is step down.
Based on the medium of core used, transformers can further be classified as; Air-core transformer and Iron-core transformer.
We also have an autotransformer wherein the primary coil and secondary coil share the same coil.

Note: The main objective of a transformer is to regulate the voltage. The transformer can either increase the output voltage as compared to the input voltage or it can do the reverse of it. In all this process, the voltage changes and so does the electric current but the frequency remains unchanged.