# Physics Problems with Solutions # Ohm's Law and Power Calculator

An online calculator to calculate the current passing through a resistor using Ohm's law and the power dissipated in a resistor given the voltage across the resistor. This calculator also calculates the voltage and current through a resistor given the power dissipated by this resistor.
Ohm's law expresses the relationship between the current I passing through a resistor and the voltage V across that resistor of resistsnce R as follows:
V = R I , I = V / R or R = V / I
The rate at which heat is dissipated in a resistor is called power P and is given in terms of current I and voltage V by:
P = V I
Using Ohm's law above, we can rewrite the power P as
P = R I
2 , P = V 2 / R

## 1 - Ohm's law and Power Calculator Given Voltage and Resistance

Enter the resistance in Ohms and the voltage in volts as positive real numbers and press "Calculate Current and Power".

 Resistance = 10Ω , Voltage = 12V Decimal Places = 4 Current = A Power = W

## 2 - Ohm's law and Power Calculator Given Power and Resistance

Enter the power in Watts and the resistance in Ohms and press "Calculate Voltage and Current".
 Power = 20W, Resistance = 30Ω Decimal Places = 4 Voltage = V Current = A