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### QUESTION OF THE DAY 09/05/2015

Question of the day September 9, 2015

Three electric lamps A, B and C are rated as follows:

Lamp A : 40 W, 220 V

Lamp B: 60 W, 220 V and

Lamp C: 100 W, 220 V

Which lamp has higher resistance? Give reason.

1. Lamp A, because it has lowest power rating. And since, voltage is constant in all the 3 cases, therefore, Resistance is inversely proportional to power.

2. (A) is the answer as by using formula R=(v^2)/p we can get answer easily

3. Answer will be lamp A, since, P = V^2/ R and therefore, resistance is inversely proportional to power. We find here that the V is comstant and the only varying quantity is P . Therefore, R will be least in lamp A
(R1 = 220/0.18 , R2 = 220/ 0.28, R3= 220/0.45)

4. Answer will be lamp A, since, P = V^2/ R and therefore, resistance is inversely proportional to power. We find here that the V is comstant and the only varying quantity is P . Therefore, R will be least in lamp A
(R1 = 220/0.18 , R2 = 220/ 0.28, R3= 220/0.45)