Question
Thu September 12, 2013 By: Praveen Kumar

On a 220 v power line the powers of the two electric bulbs are 60w and 30w separately.find the powers of their series and parallel combinations when connected on the same line

Expert Reply
Fri September 13, 2013
power, p = V2/R                               -1
where V is the voltage rating of the suppy and R is the resistance of load
thus for P1 = 60W
we can find R1
and for P2 = 30W
we can find R2
 
and for series connection net Rs = R1 + R2
and for Parallel connection, 1/Rp = 1/R1 + 1/R2
and hence power dissipated in case of Rs and Rp can be calaulated using the expression 1
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