Two lamps 100 W and 40 W are connected in series across 230 V (alternating). Which of the following statement is correct ?
Correct answer: B. 40 W lamp will glow brighter
- A. 100 W lamp will glow brighter
- B. 40 W lamp will glow brighter
- C. Both lamps will glow equally bright
- D. 40 W lamp will fuse
Explanation
At the same rated voltage, lamp resistance is R = V²/P, so the 40 W lamp has greater resistance than the 100 W lamp. In series both carry the same current, and P = I²R, making the 40 W lamp glow brighter.
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