Two lamps, one rated 100 W at 220 V and the other 200W at 220 V are connected (i) in series and (ii) in parallel ot electric main supply of 220V. Find the current drawn in each case.

In this question 

I'm able to find the answer for parallel connection in another way but able to do so for series if I follow the same methodology 

We know, the potential difference across each of the lamps is same


1/R1 + 1/R2 = 1/Rp

Multiplying V^2 on both sides of the equation, I get

V^2/R1 + V^2/R2 = V^2/Rp

Which is technically saying,

P1 + P2 = Pp 

Doing so, I get

Pp = 300W

and current drawn by the lamps is

Pp = VI

300 = 220*I

I = 15/11 = 1.36 A

im not able to find an analogy like this for series

pls help










Asked by veemadhu | 3rd Mar, 2020, 10:21: PM

Expert Answer:

Hello student,
Click on the link given below for the answer:- 

All the best!!!

Answered by Shiwani Sawant | 3rd Mar, 2020, 11:00: PM