Two exactly similar electric lamps are arranged (i) in parallel, and (ii) in series. If the parallel and series combination of lamps are connected to 220 V supply line one by one, what will be the ratio of electric power consumed by them?

As we know that

Electric power consumed = V²/R

Here V is given we have to find the value of R

So when the connection is in parallel

The equivalent resistance is

Electric power consumed in parallel connection

When the connection is in Series

The equivalent resistance = R+R = 2R

Electric power consumed in series connection

The ratio of electric power consumed by them