Calculate the energy of light with a wavelenght 486nm. Give your answer in joules and in electron volts.?

Answer 1

λ = 486 nm (1 m / 10^-9 nm) = 4.86 * 10^-7 m
λ = 4.86 * 10^-7 m
E = ?
E = hc / λ
E = (6.6260693 * 10^-34 Joules * sec) (3 * 10^8 m/sec) / (4.86 * 10^-7 m)
E = 4.090166234568 * 10^-19 Joules
E = 4.09 Joules

E = hc / λ
E = (4.13566743 * 10^-15 eV * sec) (3 * 10^8 m/sec) / (4.86 * 10^-7 m)
E = 2.5528811296296296296296296296296 * eV
E = 2.55 eV

Answer 2

Use the equation E = hc/lambda where h is Planck's constant, c is the speed of light in m/s and lambda is the wavelength (in meters). Your answer will be in Joules. There is a simple conversion factor for converting Joules into electron volts and you can find inside the cover of your text (probably).