Tue September 13, 2011 By:

2 electric bulb a and b are marked 220V,60W and 220V,100W. which one of the following will glow brighter in series and in parallel.why? elaborate it.

Expert Reply
Wed September 14, 2011
Since the bulbs are in series, same current will pass through each bulb.
But, we know that P = V2 / R.
also, Heat dissipated = I2 R.
Now, since both the bulbs are connected across the same voltage supply (220 v), resistance of 60 W bulb shall be more and it shall dissipate more heat and hence glow brightly.
Home Work Help