Question

Assertion: When a battery is short-circuited, the terminal voltage is zero.
Reason: In the situation of a short-circuit, the current is zero.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
C. Assertion is correct but Reason is incorrect
D. Assertion is incorrect but Reason is correct

Answer 1

Hint: Battery is the source of emf and it drives the flow of current. Usually batteries will have some internal resistance and this helps from damage that might be caused when the circuit is short circuited. Current and potential difference across the battery will be affected when the battery is short circuited. We can determine them by using ohm’s law.
Formula used:
$V = iR$

Complete answer:
Rate of flow of charge is known as current. A material which allows current to pass through it is known as a conductor. The property to hinder the flow of current is called resistance and a device which does that is known as a resistor.
In order to determine the amount of current that will flow when the battery is short circuited we should find out the total resistance that will be present in the circuit when the short circuit happens.
When a short circuit happens the only resistance that is present in the circuit will be internal resistance of a battery.
By using ohm's law we have
$V = iR$
$ \Rightarrow i = \dfrac{E}{r} \ne 0$
Where ‘E’ is the emf of a battery and ‘r’ is the internal resistance of a battery. Hence when the battery is short circuited current will not become zero.
External resistance is zero. The terminal difference across the battery is nothing but the potential difference across the external resistor. Since external resistance is zero the voltage across the terminals of the battery also will be zero.
So the assertion is correct and the reason is not correct.

So, the correct answer is “Option C”.

Note:
Here we have taken the voltage across the external resistor is the same as the voltage across the terminals of the battery because we can consider both will be in parallel i.e the terminals of the battery and the terminals of the external resistor and in parallel connection, potential difference will be the same.