Short circuit current will be calculated at output terminal of the network by the theorem of northern

Explanation:

The correct answer is option 'B' - Output.

Definition of Isc:
Isc stands for short-circuit current, which is the maximum current that flows in a short-circuited network or circuit. It is the current that flows when the output terminals of a network are shorted together.

Understanding Isc in a Network:
In a network or circuit, there are two main types of terminals: input terminals and output terminals. The input terminals are where the input signals or power is applied to the network, while the output terminals are where the output signals or power is obtained from the network.

Isc in a Network:
Isc is found across the output terminals of the network. When the output terminals are shorted together, it allows the maximum current to flow through the network. This short-circuit condition helps in determining the maximum current that the network can deliver.

Explanation of Options:
Let's analyze each option to understand why option 'B' is the correct answer:

a) Input: Isc is not found across the input terminals of the network. The input terminals are where the input signals or power is applied to the network, and Isc is not related to the input side of the network.

b) Output: Isc is found across the output terminals of the network. When the output terminals are shorted together, it allows the maximum current to flow through the network, helping to determine the Isc.

c) Neither input nor output: This option is incorrect because Isc is found across the output terminals of the network, as explained above.

d) Either input or output: This option is incorrect because Isc is specifically found across the output terminals of the network, not the input terminals.

Conclusion:
In conclusion, Isc is found across the output terminals of the network. It is the maximum current that flows in a short-circuited network, and determining it requires shorting the output terminals together.