Ohm's Law Calculator
Calculate voltage, current, resistance, or power using Ohm's Law (V = IR) and the power formula (P = VI). Enter any two known values to compute the rest. Essential for CBSE, JEE, and NEET Physics.
Ohm's Law Calculator
Quick Reference Table
| Quantity | Symbol | SI Unit | Formula |
|---|---|---|---|
| Voltage | V | Volt (V) | V = IR |
| Current | I | Ampere (A) | I = V/R |
| Resistance | R | Ohm (Ω) | R = V/I |
| Power | P | Watt (W) | P = VI |
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Example: A 12V battery drives 2A through a resistor.
- R = V/I = 12/2 = 6 Ω
- P = V × I = 12 × 2 = 24 W
Frequently Asked Questions
What is Ohm's Law?
Ohm's Law states that the current flowing through a conductor is directly proportional to the voltage across it and inversely proportional to its resistance. The formula is V = I × R, where V is voltage (volts), I is current (amperes), and R is resistance (ohms).
How do you calculate power from Ohm's Law?
Power (P) can be calculated using P = V × I, P = I²R, or P = V²/R. Power is measured in watts (W). These three forms are derived by substituting Ohm's Law into the basic power formula.
What are the units used in Ohm's Law?
Voltage is measured in volts (V), current in amperes (A), resistance in ohms (Ω), and power in watts (W). In board exams, always write the correct SI units with your answer — marks are deducted for missing or incorrect units.
Where is Ohm's Law used in CBSE and JEE?
Ohm's Law is covered in CBSE Class 10 (Electricity chapter) and Class 12 (Current Electricity). In JEE, it appears in circuit analysis, Kirchhoff's laws, Wheatstone bridge, and potentiometer problems. It is one of the most fundamental concepts in Physics.