Which expression correctly solves for current using voltage and resistance?

Which expression correctly solves for current using voltage and resistance?

• A. I = R / V
• B. I = P / V
• C. I = V / R
• D. I = V * R

Answer: (C)

Current is determined by how voltage drives charges through resistance. Ohm’s law shows that V = I R, so to solve for current when you know voltage and resistance, you rearrange to I = V / R. This makes sense because increasing voltage pushes more current through the same resistor, while increasing the resistance reduces the current. A quick check of units confirms this: volts divided by ohms gives amperes, which is the unit of current. For example, 10 V across 5 ohms yields 2 A. The other expressions don’t give current from voltage and resistance. R / V would invert the relationship, P / V uses power rather than resistance, and V times R yields a quantity with incompatible units for current.

Current is determined by how voltage drives charges through resistance. Ohm’s law shows that V = I R, so to solve for current when you know voltage and resistance, you rearrange to I = V / R. This makes sense because increasing voltage pushes more current through the same resistor, while increasing the resistance reduces the current.

A quick check of units confirms this: volts divided by ohms gives amperes, which is the unit of current. For example, 10 V across 5 ohms yields 2 A.

The other expressions don’t give current from voltage and resistance. R / V would invert the relationship, P / V uses power rather than resistance, and V times R yields a quantity with incompatible units for current.