Q: How do you calculate power using Ohm's Law?

Power can be found three ways: P = V × I , P = I² × R , or P = V² ÷ R . For example, 230V across a 23Ω element gives I = 10A and P = 230 × 10 = 2300W.

Q: How do you find resistance from voltage and current?

Rearrange Ohm's Law to R = V ÷ I . If a circuit draws 5A at 230V, the resistance is 230 ÷ 5 = 46Ω. Measuring resistance this way (volt-drop test) is common when fault finding.

Q: What are the four Ohm's Law formulas?

The four core relationships are: V = I × R (voltage), I = V ÷ R (current), R = V ÷ I (resistance), and P = V × I (power). Combined with the power equations P = I²R and P = V²/R, these solve almost any resistive circuit.

Question 1

What is Ohm's Law?

Accepted Answer

Ohm's Law states that voltage equals current multiplied by resistance: V = I × R. Rearranged, current I = V ÷ R and resistance R = V ÷ I. It is the fundamental relationship for any DC circuit and for resistive AC circuits.

Question 2

How do you calculate power using Ohm's Law?

Accepted Answer

Power can be found three ways: P = V × I, P = I² × R, or P = V² ÷ R. For example, 230V across a 23Ω element gives I = 10A and P = 230 × 10 = 2300W.

Question 3

How do you find resistance from voltage and current?

Accepted Answer

Rearrange Ohm's Law to R = V ÷ I. If a circuit draws 5A at 230V, the resistance is 230 ÷ 5 = 46Ω. Measuring resistance this way (volt-drop test) is common when fault finding.

Question 4

What are the four Ohm's Law formulas?

Accepted Answer

The four core relationships are: V = I × R (voltage), I = V ÷ R (current), R = V ÷ I (resistance), and P = V × I (power). Combined with the power equations P = I²R and P = V²/R, these solve almost any resistive circuit.

Ohm's Law Calculator