When light falls on an ordinary piece of glass, how much is reflected?

Think it through first, then pick an option.

a 0.4% - 0.5%
b 4% - 5%
c 14% - 15%
d 24% - 25%

Answer and explanation

Correct answer: b 4% - 5%

An ordinary piece of glass reflects little, only 4% to 5%; the rest is refracted through. Near 80° or 90° of incidence the reflection does rise sharply.

Why the other options are wrong

a 0.4% - 0.5%: This is not the answer: An ordinary piece of glass reflects only 4% to 5%; the rest is refracted through. This figure does not match 4% to 5%.
c 14% - 15%: This is not the answer: An ordinary piece of glass reflects only 4% to 5%; the rest is refracted through. This figure does not match 4% to 5%.
d 24% - 25%: This is not the answer: An ordinary piece of glass reflects only 4% to 5%; the rest is refracted through. This figure does not match 4% to 5%.