An energy-saving light bulb has an efficiency of 45%. if 5w of light is emitted, what electrical power is required

If you're using the bulb as a source of light, then it's. 14/60 = 23.3% efficient.

If you're using it to heat a bird nest or a hamster cage, then it's. 46/60 = 76.7% efficient !

It just depends on your point of view, and what you consider 'useful' output.

the moon affects the earth gravitation ally, causing certain motions of that body and also producing tides in its ocean and atmosphere. the tidal wave in our atmosphere is, however, far too minute to be an effective cause in any known meteorological phenomenon.

explanation: