Final answer:
The 12 volt car battery releases 18 watts of power is an example of electric power and circuit calculations in physics. The current for a device can be found using P = IV, and the number of electrons passing through can be determined by dividing the total charge by the charge of a single electron.
Step-by-step explanation:
The subject matter at hand involves the power output of a 12 volt battery and the current it provides, as well as the properties of an electric circuit related to it. To aid in conceptual understanding, let's dissect a related example:
A 12-V car battery releases 18 watts of power, meaning it does 18 joules of work per second. If we consider an electrical device, like a lamp rated at 20.00 W and 12.00 V, the current drawn by the lamp (I) can be found using the formula P = IV, where P is the power and V is the voltage. Substituting the given values, I = P/V, which gives I = 20.00 W / 12.00 V, yielding a current I = 1.67 A.
To calculate how many electrons move through a headlight each second, you need to find the charge that moves in 1 second (Q) using the lamp power and voltage: Q = P/V, with a slight rearrangement, it becomes Q = (30.0 W) / (12.0 V), which results in Q = 2.5 C. Considering that one electron has a charge of approximately 1.602 x 10-19 C, the number of electrons (n) can be calculated by dividing the total charge Q by the charge per electron, which gives n = Q / (1.602 x 10-19 C). Substituting the value of Q results in 1.56 x 1019 electrons passing through each second.