What Is the Resistance and Power for 100V and 0.1A?

With 100 volts across a 1,000-ohm load, 0.1 amps flow and 10 watts are dissipated. These four values (voltage, current, resistance, and power) are the foundation of every electrical calculation on this site.

100V and 0.1A
1,000 Ω   |   10 W
Voltage (V)100 V
Current (I)0.1 A
Resistance (R)1,000 Ω
Power (P)10 W
1,000
10

Formulas & Step-by-Step

Resistance

R = V ÷ I

100 ÷ 0.1 = 1,000 Ω

Power

P = V × I

100 × 0.1 = 10 W

Verification (alternative formulas)

P = I² × R

0.1² × 1,000 = 0.01 × 1,000 = 10 W

P = V² ÷ R

100² ÷ 1,000 = 10,000 ÷ 1,000 = 10 W

Circuit Analysis

Heat Dissipation

This circuit dissipates 10 watts of power as heat. In a resistor, all electrical energy at steady state converts to thermal energy. The actual component power rating needs headroom above this steady-state figure, but the specific derating depends on resistor type (carbon-comp, metal-film, wirewound each behave differently), ambient temperature, airflow or heat-sinking, and whether the load is continuous or pulsed. Check the resistor datasheet for the manufacturer-specific derating curve rather than applying a blanket margin.

If You Change the Resistance

ResistanceCurrentPowerChange
500 Ω0.2 A20 WLower R = more current
750 Ω0.1333 A13.33 WLower R = more current
1,000 Ω0.1 A10 WCurrent
1,500 Ω0.0667 A6.67 WHigher R = less current
2,000 Ω0.05 A5 WHigher R = less current

Same Resistance at Different Voltages

Holding the resistance constant at 1,000Ω, here is how current and power scale with source voltage. This is a reference table, not a set of separate circuit scenarios: each row is the same resistor under a different applied voltage.

VoltageCurrent (at 1,000Ω)Power
5V0.005 A0.025 W
12V0.012 A0.144 W
24V0.024 A0.576 W
48V0.048 A2.3 W
120V0.12 A14.4 W
208V0.208 A43.26 W
230V0.23 A52.9 W
240V0.24 A57.6 W
480V0.48 A230.4 W

Frequently Asked Questions

R = V ÷ I = 100 ÷ 0.1 = 1,000 ohms.
For purely resistive loads, yes. For reactive loads, use impedance (Z) instead of resistance (R). Z includes both resistance and reactance, and the V/I phase shift shows up in power factor.
Ohm's Law (V = IR) and the power equation (P = VI) connect all four. Given any two, you can calculate the other two.
P = V × I = 100 × 0.1 = 10 watts.
At the same 100V, current doubles to 0.2A and power quadruples to 20W. Lower resistance means more current, which means more power dissipated as heat.
This calculator provides estimates for reference purposes only. Always consult a licensed electrician and verify compliance with the National Electrical Code (NEC) and local electrical codes before performing any electrical work.