Question

Explain application of ohm’s law to a complete circuit.

Answer 1

Hint:Ohm’s have given a relationship between three quantities: the current, voltage and resistance of the circuit. Ohm’s law states that the voltage or potential difference between two points is directly proportional to the current in the circuit. Draw a linear circuit containing battery and resistance, and determine the current in the circuit.

Complete Step by Step Answer:
We have Ohm’s law which states that the voltage or potential difference between two points is directly proportional to the current in the circuit. Therefore, we can express the Ohm’s law as,
\[V \propto I\]
\[ \Rightarrow V = IR\]
Where V is the voltage, I is the current passing through the circuit. The constant of proportionality is the resistance R of the circuit.

The German scientist George Simon Ohm has discovered the relationship between current, voltage and resistance in the circuit.Using Ohm’s law, we can determine the current flowing through the circuit if the resistance in the circuit and the emf of the supply is known to us. For example, let’s consider the circuit below.

In the above circuit, the resistance R is connected in series with the DC battery of emf 12 V. By using Ohm’s law, we can calculate the current in the above circuit as,
\[V = IR\]
\[ \Rightarrow 12 = \left( I \right)\left( {200} \right)\]
\[ \therefore I = 0.06\,{\text{A}}\]
Thus, the unknown current is 0.06 ampere.

Additional Information:
We know as per the Ohm’s law voltage/current=$a$constant and that constant is resistance. But resistance does not remain constant all the time. When the temperature of material changes the resistance also changes. The law is not applicable to unilateral networks. Unilateral networks allow the current to flow in one direction. Ohm’s law is also not applicable to non-linear elements. The relation between V and I depends on the sign of V where V is voltage and I is current in circuit.

Note: Ohm’s law is not applicable to unilateral networks which involve diode and transmitter, etc. If we have a number of resistors in the circuit, the Ohm’s law is still applicable. To determine the current, the first thing that we have to do is to determine the total resistance in the circuit. If there are two emfs in the circuit, we cannot follow Ohm's law.