Question

In series combination, which remains constant?
A. Voltage
B. Current
C. Both voltage and current
D. Both are variables

Answer 1

Hint: In a series combination, the charge flowing through the different components in the combination remains constant. Therefore, the charge flowing per unit time through these components remains constant since there is no accumulation of charge in any component in the combination.

Complete step-by-step answer:
In a series combination of components in an electric circuit, the same electric charge flows through each component. This is because there is continuity in the charge flowing. There is no accumulation of charge anywhere in the circuit. Hence, since, the electric charge flowing in the series circuit has to remain constant, the electric charge flowing per second in the circuit also has to remain constant.
Now, the electric charge flowing per second through the circuit is known as the electric current in the circuit. Hence, as explained above, the electric current remains constant in a series combination.
Hence, the correct option is B) Current.

Additional information:
In the series circuit, as electric current flows through the resistors and other components of a series circuit, the potential drops with each component. Hence, the voltage does not remain constant in a series circuit. Voltage remains constant in a parallel circuit combination.

Note: Students might get confused as to why does voltage not remain constant in a series circuit, however they must understand that if the voltage remains constant, even after passing through a component in the circuit, then current will not flow in the circuit, since the reason why current flows is that there is a potential difference in the circuit. If the voltage remains constant and there is no potential drop in the circuit, then current will not be able to flow.