Question

A 25 W and a 100 W bulb are joined in series and connected to the mains. Which bulb will glow brighter?

Answer 1

in series, the current flowing through both bulbs will be same...

let voltage rating of both bulbs is 220 V.

that bulb will glow brighter which dissipates more energy or power.

power dissipated = (i^2) R

but ,

R = (rating voltage)^2 / (rating power)

so,

power dissipated = (i × 220)^2 / (rating power)

here, i is same for both bulbs ,

so, power dissipated is inversely proportional to power rating of the bulbs.

so, power dissipation will be more in 25 W bulb.

hence, 25 W bulb will glow brighter.

...........

hope , you got the solution.

Answer 2

The answer is in the attachment below.....hope it will help you dear....