Question

How is electrical power calculated in a circuit?

Answer 1

Electrical power in a circuit is calculated using the formula:

Power (P) = Voltage (V) × Current (I)

Where:

Power (P) is measured in watts (W)
Voltage (V) is measured in volts (V)
Current (I) is measured in amperes or amps (A)

This formula is derived from Ohm's law, which states that the current flowing through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance between them. Mathematically, Ohm's law is represented as:

I = V / R

Where:

I is the current in amperes (A)
V is the voltage in volts (V)
R is the resistance in ohms (Ω)

Using Ohm's law, you can rearrange the formula to solve for voltage:

V = I × R

Substitute this expression for voltage into the power formula:

P = I × R × I

Simplify:

P = I^2 × R

This is another form of the power formula that involves resistance and current squared.

Similarly, you can rearrange Ohm's law to solve for current:

I = V / R

Substitute this expression for current into the power formula:

P = V × V / R

Simplify:

P = V^2 / R

This is the third form of the power formula involving voltage squared and resistance.

In summary, you can calculate electrical power in a circuit using any of the following formulas:

P = V × I
P = I^2 × R
P = V^2 / R

Make sure to use the appropriate units (volts for voltage, amperes for current, ohms for resistance) to ensure consistent and accurate calculations.