A circuit is a closed loop of wire with sources (batteries) and components (resistors, lights, etc.).
Try this
2
Ohm's law: voltage V = I · R (here R = 10 Ω) = 20.0 V
Ohm's law
Volts = amps × ohms. Rearrange to find any one from the other two: I = V/R, R = V/I.
Series vs parallel
- Series — one loop, same current everywhere; resistances add up; if one bulb dies, all go out.
- Parallel — separate branches, same voltage across each; total resistance is *less* than the smallest branch; one bulb dying doesn't stop the others.
Your turn
A 12 V battery drives 0.5 A through a bulb. What's the bulb's resistance?
Ohm's law