Practice question · Numerical answer
A 24 volt supply is connected across a 6 ohm resistor. What current flows, in amperes?
Hints
- Ohm's law says current equals voltage divided by resistance.
- 24 divided by 6.
Show the answer
4
Why
Ohm's law gives I = V/R = 24/6 = 4 amperes.
The relationship is worth reading as a statement about what each quantity does: voltage is the push, resistance is the opposition, and current is what results. Doubling the voltage doubles the current; doubling the resistance halves it.
The power dissipated follows as P = VI = 24 x 4 = 96 watts, all of it becoming heat in the resistor - which is why resistors have power ratings and why a component rated for a quarter of a watt fails immediately in a circuit like this one.
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