CSLB C-10 Electrical ContractorElectrical Theory and CalculationsEasy
A 120V circuit powers a resistive heating element with a resistance of 10 ohms. What is the approximate current drawn by the heating element?
- A12 A
- B0.12 A
- C1.2 A
- D120 A
Show answer & explanationAnswer & explanation
Correct answer: A. 12 A
Using Ohm's Law, Current (I) = Voltage (V) / Resistance (R). So, I = 120V / 10Ω = 12A.
Why the other options are wrong
- B. This would be if voltage was 12V, or a calculation error.
- C. This would be if resistance was 100 ohms, or a calculation error.
- D. This would be if resistance was 1 ohm, or a calculation error.
Ohm's Law (Current)
Ohm's Law states that the current (I) in a circuit is equal to the voltage (V) divided by the resistance (R).
- I = V / R
- Fundamental to circuit analysis.
- Applies to DC circuits and resistive AC circuits.
Memory trick: Current 'I' is Voltage 'V' over Resistance 'R'.