Question

Calculate the energy of electromagnetic radiation of wavelength 450nm

Answer 1

Wavelength = 450 nm = 450 * 10^-9 m = 4.5 * 10^-7 m

Since it's an electromagnetic radiation
The speed of the wave = c = 3*10^8 m/s

Therefore,
Frequency = c/wavelength = 3*10^8 / 4.5*10^-7 = 0.66 *10^15 = 6.67*10^14 Hertz

Therefore,
Energy = Planck's constant * Frequency
= 6.626*10^-34 * 6.67*10^14 Joules
= 44.195 * 10^-20
= 4.42*10^-19 Joules = 2.7625 Electron volts

Answer 2

1242/450 ev = 2.76 ev