Which one is having lesser resistance - 60w bulb or 40w bulb

Resistance of bulb is related by power by the following relation

now we will have

so here we can say that resistance of bulb is inversely depends on power of the bulb

So here the bulb with less power will have more resistance.

So 60 W bulb will have lesser resistance than 40 W bulb.

you get 2.3=1.21*\frac{a}2 or 4.6=1.21a or a=3.802 (b)

explanation: