A total charge of 100C flows through a 12W bulb in a time of 50 second. What is the potential difference across the bulb during this time?
Correct answer: C. 6.0V
- A. 0.12V
- B. 2.0V
- C. 6.0V
- D. 24V
Explanation
The correct answer is 6.0V, determined by using the formula P = VI, where P is power, V is voltage, and I is current. Given the power of the bulb is 12W and the current is calculated from the charge and time as 2A (100C / 50s), we find V = 12W / 2A = 6V. This satisfies the power equation perfectly.Option A (0.12V) is incorrect because it implies an unrealistically low power. Option B (2.0V) is incorrect because the resulting power equation doesn't match the conditions. Option D (24V) is incorrect because it suggests a current that would only transfer 25C, not the given 100C.
This question appeared on the ETEA MDCAT 2016 paper, which you can sit online with every answer explained.
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