A lightbulb has an efficiency of 13.1%.How much light energy (not heat energy) is generated by the bulb every second if the bulb has a power pf 8W?

1.048 W

Explanation: Given that a lightbulb has an efficiency of 13.1%.How much light energy (not heat energy) is generated by the bulb every second if the bulb has a power pf 8W?

The input power = 8W

The output power = ?

The efficiency = 13.1%

Using the formula below:

Efficiency = (power output / power input) × 100

13.1 = (Power output / 8 ) × 100

0.131 = power output / 8

Cross multiply to make the power output the subject of formula

Power output = 0.131 × 8

Power output = 1.048 W

Therefore, the light energy (not heat energy) generated by the bulb every second is 1.048 W

answer: 802.3 kilo joules of energy represents 191.75 kilo calorie of energy.

explanation:

energy released during combustion of one mole methane = 802.3 kilo joules

if 1 kilo joule = 0.239006   kilo calorie

then ,802.3 kilo joule will be = 802.30.239006 kilo calorie

802.3 kilo joule = 191.75 kilo calorie

hence, the energy in kilo calorie is 191.75 kilo calorie.