4. what would you notice if you stood under an energy efficient light bulb compared with standing under a normal light bulb?

More energy used also means more heat is produced. Considering the purpose of a light bulb is to produce light – not heat – any energy that goes in to producing heat is wasted. In other words, a bulb that produces more heat for the same light output is less efficient.

You would probably notice more heat and it would be brighter.