Two bulbs, one 250V, 100 W and second 250V, 25 W are connected in series and 440V AC, 50Hz is applied across the two bulbs. Which of the following will happen,
- A. 100 W bulb glows bright compare to 25 W bulb
- B. both 100 W bulb & 25 W bulb will glow normal
- C. 25W bulb will burn-out
- D. 25 W bulb glows bright compare to 100 W bulb
Answer: C. 25W bulb will burn-out
Explanation: R1 = 625 Ω, R2 = 2500 Ω; V across the 25 W bulb = 440×2500/3125 = 352 V > 250 V, so it burns out.