The power dissipated by something with voltage across it is
(voltage)² / (resistance) .
You can see that resistance is in the denominator of the fraction,
so larger resistances dissipate less power, and smaller resistances
dissipate more power.
Here's an easy way to remember it:
-- Connecting a piece of rubber (high resistance) across the terminals of a battery
uses very little power from the battery.
-- Laying a piece of wire (low resistance) across the terminals of a battery
may draw so much power from the battery that the wire melts.
Since the voltage across both bulbs is expected to be the same, the bulb
designed to dissipate 60 watts has higher resistance than the one designed
to dissipate 100 watts.
