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CBSE Class 10 Answered

Two light bulbs are marked 230 V; 75 W and 230 V; 150 W. If the first bulb has a resistance R, then the resistance of the second is?
Asked by Archana | 10 May, 2019, 19:59: PM
answered-by-expert Expert Answer
Power = voltage×current = Voltage×(Voltage/Resistance)
 
Hence if P is power, V is voltage  and R is resistance, then R = V 2 / P
 
hence for first bulb, R1  = V 2 / 75 = R
for second bulb,  R2 = V 2 /150 = (1/2)(V2 / 75) = R/2
Answered by Thiyagarajan K | 11 May, 2019, 08:25: AM

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