Two electric bulbs marked 100W 220V and 200W 200V have tungsten filament of same length. Which of the two bulbs will have thicker filament?
P = V2/R
⇒More the power, lesser the resistance.
The resistance of 200W bulb is lesser than the 100W bulb.
R = ρ l/A
⇒Higher the resistance,lesser will be the value of A. Thus, thinner will be the wire.
The wire of 200W bulb is thicker than 100W bulb, as it's resistance is lesser.