2025 · Q112
The potential difference between the terminals of an electrical heating device is 40 V, when it draws a current of 2 A from the source. Which one of the following is the correct value of current drawn by the heating device if the potential is increased to 140 V?
general-sciencephysics-light-electricity
- A7 A
- B5 A
- C4 A
- D2 A
Explanation
The heating device has resistance R = V/I = 40/2 = 20 ohms. Assuming the resistance stays constant, at 140 V the current is I = V/R = 140/20 = 7 A.