Amps can be calculated by: A. E / R, B. W / E, C. The square root of W / R, D. All of the above

• A. E / R
• B. W / E
• C. The square root of W / R
• D. All of the above

Answer: (D)

Current in amperes can be found from different relationships that come from Ohm’s law and power equations. The basic form is I = V / R, which uses voltage across a component and its resistance. That shows why the first expression is valid.

If you know the power dissipated and the voltage, use P = V I, rearranged as I = P / V. That corresponds to the second expression, so it’s also a correct way to find current when power and voltage are known.

If you know the power and the resistance, use P = I^2 R, rearranged as I = sqrt(P / R). This gives the third expression, valid when power and resistance are known.

All three are correct because they are equivalent ways to express current using consistent quantities (I in amperes, V or E for voltage in volts, P or W for power in watts, and R for resistance in ohms).