Question

At the time of short circuit, the current in the circuit:
(A). Does not change
(B). Keeps on increasing and decreasing continuously
(C). Decreases considerably
(D). Increases heavily

Answer 1

Hint: Use ohm’s law to get relation between voltage, resistance and current. Ohms law is given as$V=IR$. As you can see Voltage is directly proportional to current and resistance while current inversely proportional to resistance. Ohm's law is valid only when the graph of voltage versus current must pass through origin. Value of voltage will be zero in the short circuit and the value of current is high. But the value of voltage will be high in an open circuit and the value of current will be zero.

Complete step by step answer:
As an example, let’s take a circuit having a capacitor whose resistance is very low. Capacitor has two poles or terminals. Join wire to the positive and negative terminal of the capacitor. When current in the capacitor flows excessively, at that time a short circuit happens because R=0. Short circuit occurs when resistance of that device i.e. internal resistance and resistance that we apply to the circuit i.e. external resistance cannot resist it since R=0.
At the time of short circuit, large amounts of current flow means current increases and large amounts of energy is delivered through the circuit.
We can understand this concept by ohm’s law also, which is given by,
V = IR
Where,
V = voltage
I = current
R = resistance
From the above equation we can say that voltage is directly proportional to current and current is inversely proportional to resistance.

So option D is correct. : At the time of short circuit, the current in the circuit increases heavily

Note: Voltage is directly proportional to current and resistance while current inversely proportional to resistance. So at the time of short circuit, value of voltage is low and value of current is high. There are two types of resistance: one is external resistance and other is internal resistance. External resistance is the resistance applied to the circuit eternally. While internal resistance is the resistance present in the device. That is, we can say that each device has its own internal resistance. To solve numericals, depending on the concept given in question, use KVL and KCL formulae.