Two bulbs have the following ratings 1. 40W, 220V. 2. 20W, 100V. the ratio of their resistance is ___.
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Answer:
V2/P
Explanation:
Where P = power of the bulb V = voltage across the bulb R = resistance of the bulbEquation of power in terms of voltage and resistance is
P = V^2/R Or
R = V^2/P
R1 = 220^2/40 = 1210 ohm
R2 = 110^2/20 = 605
R1 : R2 = 1210 : 605
R1 : R2 = 2:1
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