Final answer:
A lightning flash transferring 15 C of charge through a potential difference of 10 V can light a 75 W bulb for only 0.0333 minutes, or 2 seconds, which is not listed in the multiple-choice options.
Step-by-step explanation:
The question asks how long a 75 W light bulb can be lit by the energy from a lightning flash that transfers 15 C of charge through a potential difference of 10 V. To answer this, we first need to calculate the total energy transferred by the lightning using the formula E = QV where E is energy, Q is charge, and V is potential difference. By substituting, we get E = (15 C)(10 V) = 150 J (joules).
Next, we need to determine how long the 75 W bulb can be lit with this amount of energy. The power of the bulb P is given by P = E/t, or rearranged, the time t = E/P. Substituting the values, we find t = 150 J / 75 W = 2 seconds. Since 1 minute is 60 seconds, the time in minutes is 2 seconds / 60 = 0.0333 minutes. Therefore, none of the options a) 2.5 minutes b) 5 minutes c) 7.5 minutes d) 10 minutes are correct; the answer is actually less than a minute.