Ohm”s law has central importance in the study of electricity. German scientist George ohm established the animation relation between the voltage V and the current I flowing through the circuit due to this voltage. If the current across the conductor is I when the voltage across it is V then the resistance R in animation is given as,

R = ‘(V)/(I)’

The resistance of the conductor is referred as ohm in ohms law animation which contains the 1 ampere current while 1 volt of voltage is applied across it.

Experiment in Ohms Law

The circuit is constructed with variable battery V, A resistance R and a key and the ammeter, voltmeter is connected for measuring the current passing through the circuit and the resistor voltage respectively. The needle like stroke bar is connected to the motorbike. In the place of resistor you can join a small lamp. The ohms law animation is considered as the given circuit,

ohms law

Ratio Calculation of Ohm’s Law

The ratio calculation for the voltage V and the current I provide the value of the resistance. The graph is plotted for the difference in the voltage and the current. The graph is drawn by taking the voltage on the horizontal axis and the current on the vertical axis.

The conclusions for the ratio and calculation by using ohms law in animation is given here,

There is increase in current in linear with the increase in voltage.

The straight line passing through center is obtained in the current voltage graph.

Ratio of the current and the voltage is constant in all the cases.

According to the ohms law, conductor which passes the current is directly proportional to the difference in potential across the conductor.

V ‘alpha’I

V = IR

The R is considered as the constant for the proportionality which gives the resistance of the wire. The resistance now acquires the properties of the metallic wire. The movement of the electrons here is defined for the moving of the electrons and also the atoms of the molecules. The atoms and the molecules attains the collision in the flow of electrons. The electron thus obtained cannot move freely and it is retarded by the resistance of the conductor. The conductors which is considered as good is defined as copper, aluminum. Hence the domestic wiring was done by copper wire.

From the above equation,

Resistance (R) = ‘(V)/(current (I))’ = ‘(V)/(Ampere A)’ = ohm( O).

Here the resistance is measured by using ohm.

Ohms law is probably the most importantl law in electrical subject. It states “The current passes through a element is directly proportional to the voltage applied between the terminal of the same item. In other words we can say that when a voltage is applied across a load, the resulting current is a direct proportion of the voltage. In mathematical notations,

V a I

or, V = RI, where V is the voltage, I is the current and R is a constant. The constant R is defined as the resistance of the circuit.

The concept of Ohms law is very widely used. In this section we will study its application in parallel circuit.

What is a Parallel Circuit:

ohms law parallel

In the above diagram a parallel circuit is shown consisting two resistors having values of resistances as R1 and R2

An electrical source provides a voltage of V which is applied to a circuit consisting two resistors connected in parallel between points A and B.

Applying Ohms law for each branch of the parallel circuit,

V = I1R1 and also V = I2R2

Inferences from Ohms Law in a Parallel Circuit:

As mentioned earlier, the voltage between A and B is same as supply voltage V.

Therefore, as per ohms law,

V = I1R1 or I1 = $ frac{V}{R_1 }$

V = I2R2 or I2 = $ frac{V}{R_2 }$

But the total current I is the sum of the branch currents. That is, I = I1+ I2

Let R be the effective resistance of the entire circuit.

Therefore, $ frac{V}{R }$ = $ frac{V}{R_1 }$ + $ frac{V}{R_2 }$

or, $ frac{1}{R }$ = $ frac{1}{R_1 }$ + $ frac{1}{R_2 }$

Thus Ohms law helps us to find the value of R which is the equivalent resistance of the resistances in parallel.

The total consumption of power of the circuit can also be found

Let the total power consumed P and it is equal to P1 + P2

P1= VI1 and P2= VI2 or as per Ohms law, P1= I12 R1 and P2= I22 R2