Two bulbs of 500 W and 200 W rated at 250 V will have resistance ratio as:
Correct answer: B. 2 : 5
- A. 4 : 25
- B. 2 : 5
- C. 25 : 4
- D. 5 : 2
Explanation
P = V2/R Bulb 1= 500W, 250V Bulb 2 = 200W, 250V Let's calculate, For Bulb 1. R1 = (V1)2/P1= (250V)2/500W For Bulb 2 R2 = (V2)2/P2 =(250V)2/500W Now, R1= 125 ohm R2= 312.5 ohm R1/R2=125/312.5=2/5=2:5
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