If sunlight on the Earth equaled a 100 watt bulb, how big a bulb would you get on Jupiter?
Jupiter is 5.2 times as far away as the Earth from the Sun, so the light it gets is (5.2)^2 = 27 times fainter, and so if you have a 100 watt bulb on the earth, on Jupiter the illumination would only be about 3-4 watts!