Electrician Red Seal · Question
When an incandescent light bulb is first turned on, its filament has a significantly lower resistance compared to when it reaches its operating temperature. What is the most direct consequence of this characteristic?
Incandescent filaments are made of materials whose resistance increases with temperature. When cold, the resistance is low, leading to a high initial current (i
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Question: When an incandescent light bulb is first turned on, its filament has a significantly lower resistance compared to when it reaches its operating temperature. What is the most direct consequence of this characteristic?
Answer options:
- The bulb draws less current initially.
- The bulb's power consumption decreases as it heats up. ✅ The bulb experiences a high inrush current.
- The bulb's luminous efficiency increases instantly.
Correct answer: The bulb experiences a high inrush current.
Explanation: Incandescent filaments are made of materials whose resistance increases with temperature. When cold, the resistance is low, leading to a high initial current (inrush current) according to Ohm's Law (I = V/R). As the filament heats up, its resistance increases, and the current drawn decreases to its steady-state operating value.
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