1. A light bulb is rated at 100W, 115V. What steady current flows through if for
ID: 1952398 • Letter: 1
Question
1. A light bulb is rated at 100W, 115V. What steady current flows through if for these values?2. A car battery has an emf of 12.6V. You connect a light bulb across its terminals that has a resistance of 17.6 ohms at this voltage. Calculate the rate at which chemical energy is being converted to electrical energy in the battery and delivered to the light bult. You can neglect the internal resistance of the battery.
3. A 12.6V source of emf does 12.6 joules of _______ on each coulomb of __________ that passes through it.
Explanation / Answer
1) For this we can use the equation that P = iV P = power (100 W) V = potential difference (115 V) i = current P = iV i = P/V = (100 W)/(115 V) = 0.87 A of current 2) For this we use the above equation P = iV, but we also can use Ohm's Law to substitute for i (V = iR) V = iR i = V/R P = iV = (V/R)V = (V^2)/R Now we can plug in what we have P = (12.6^2 V)/17.6 ohms = 9.02 W 3) Electric potential is potential energy per unit charge. So the 12.6 V source does 12.6 joules of WORK on each coulomb of CHARGE that passes through it
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