Which equation represents Ohm's Law for current?

Which equation represents Ohm's Law for current?

• A. I = V / R
• B. I = R / V
• C. I = V × R
• D. I = V + R

Answer: (A)

Current is the rate at which charge flows, and Ohm's Law shows how it depends on voltage and resistance. The correct relationship is current equals voltage divided by resistance. This form directly expresses that increasing voltage while holding resistance steady increases current, and increasing resistance while holding voltage steady decreases current. The units line up neatly: volts divided by ohms gives amperes, which is the unit of current. For example, with 9 volts across 3 ohms, the current is 9/3 = 3 amperes. The other expressions don’t fit Ohm’s Law: multiplying voltage by resistance would give volt-ohms (not amperes); inverting the ratio would yield ohms per volt (not amperes); and adding voltage and resistance mixes incompatible quantities.

Current is the rate at which charge flows, and Ohm's Law shows how it depends on voltage and resistance. The correct relationship is current equals voltage divided by resistance. This form directly expresses that increasing voltage while holding resistance steady increases current, and increasing resistance while holding voltage steady decreases current. The units line up neatly: volts divided by ohms gives amperes, which is the unit of current.

For example, with 9 volts across 3 ohms, the current is 9/3 = 3 amperes. The other expressions don’t fit Ohm’s Law: multiplying voltage by resistance would give volt-ohms (not amperes); inverting the ratio would yield ohms per volt (not amperes); and adding voltage and resistance mixes incompatible quantities.