Watt is a unit of power that is a simplified form of the quotient of joules and seconds.
1 Watt = 1 joule / second
It is known that 1 hour is equal to 60 minutes that is also equal to 60 seconds. Converting 1 hour to second,
1 hour x (60 minutes/1 hour) x (60 seconds/1 minute) = 3600 sec
Thus, for every hour, there is 3600 seconds.
Energy = (100 Joule/second)(3600 s)
Energy = 360,000 joule
Thus, the energy emitted by the bulb is equal to 360,000 joule.