Question

If a 60 W light bulb, powered with 620,000 J of energy, in a bedside lamp is only 20 percent efficient in converting electrical energy into light energy, how many joules of light energy does this light bulb produce each time?

Answer 1

720 Joules

Step-by-step explanation:

Given: 60 W light bulb powered by 620,000 J of energy. 20 percent efficient in converting electrical energy into light energy

To find: how many joules of light energy does this light bulb produce each time?

Formula:
`E = (hc)/(A)`

Solution: The total amount of energy generated by the light bulb every minute is 3600 Joules. If the light bulb is only twenty (20) percent efficient in converting that energy to visible light energy, that would be twenty percent of the total.

E (Joules) = P (Watts) X t (seconds)

E = 60 W X 60 seconds

E = 3600 Joules of energy

20% of 3600 = 720 Joules

Therefore, it produces 720 joules of light each time.