Which one of the following bulbs has the least resistance, if the current is kept constant?
Correct answer: D. 400 watt
- A. 100 watt
- B. 200 watt
- C. 300 watt
- D. 400 watt
Explanation
In this question, we are asked to determine which bulb has the least resistance when the current is kept constant. According to Ohm's law, the resistance (R) of a device is inversely proportional to its power (P) when the current (I) is constant, represented by the formula R = V/I, where V = P/I. Therefore, a bulb with higher wattage consumes more power for the same current, resulting in lower resistance. Thus, the 400 watt bulb has the least resistance, while the 100, 200, and 300 watt bulbs have higher resistances respectively.
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Steady current relates charge flow to potential difference, resistance and resistivity, including how temperature changes a conductor's resistance. Sources with internal resistance have terminal voltage below their emf when delivering current, and maximum power output occurs under a specific load condition rather than at zero resistance.
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