What is the heat generated with a 40Watt bulb when its for 2 hours?

Let's assume that this is an incandescent bulb with a light efficiency of 35 percent ... i.e. 35 percent of the electric power it consumes is converted to light, and the other 65 percent becomes heat, which the bulb then dissipates into the room. So the bulb is dissipating heat at the rate of (0.65 x 40) = 26 watts = 26 Joules per second. 2 hours = (2 x 3,600) = 7,200 seconds 26 joules per second x 7,200 seconds = 187,200 Joules of heat