Idea 9of 9Builds onPush, flow, fightHow fast you pay
Watts in the wire
12 V and 2 A. How fast is energy spent?
Today you'll discover
- what a bulb spends each second
- how volts and amps set it together
- the number printed on every appliance
Think first12 V drives 2 A through a bulb
A 12 V battery drives 2 A through a bulb. How many joules does the bulb spend each second?
Decide first, then press Next. Multiply the volts on the battery by the amps on the wire.
A loop with a battery and one bulb, the volts, amps and the bulb's watts printed. After a prediction, the battery's volts are read as joules per coulomb, then the current as coulombs per second, then their product is named. The last step asks the current a kettle draws from its watts and volts.
See the whole ideathe big idea and the key word, in one place
The big idea
Electrical power is volts times amps: P = V I.
Why it happensA bulb's brightness is energy per second. Raise the volts or the amps and it spends faster. The watts printed on any appliance are this product.
Key word
- electrical power
- the rate a component spends electrical energy, in watts: P = V I, volts times amps
About this modelCharge is never used up: what leaves the battery comes back. Volts are what get spent.
Charge is never used up: what leaves the battery comes back. Volts are what get spent.
Ready to use it?
- Use P = V I to find the power, current or voltage of a described appliance.