With a wavelength of 436nm (1nm = 10^-9m) what is the frequency of this radiation?

Question

Excited mercury atoms emit light strongly at a wavelength

of 436 nm (1 nm = 10-9 m).

(a) What is the frequency of this radiation?

(b) What is the energy of this radiation?

(c) Predict the color associated with this wavelength?

Answer 1

(a) Use  c = freq x wavelength

(b) Use  E = hf

(c) look up an E-M radiation colour chart!!!... found in your Physics text book!!!

Answer 2

(a) The relationship between frequency and wavelength is given by the formula

c = frequency x wavelength

where c is the speed of light or 299,792,459 m/s

therefore frequency = 299,792,459 / wavelength

frequency = 299,792,459 / 436 x 10^-9 = 6.876 x 10^14 Hz

(b) The relationship between energy and frequency is given by the formula

E = h x frequency

where h is Planck's constant or 6.626 068 96 x 10^-34 J.s

therefore energy = 6.626 068 96 x 10^-34 * 6.876 x 10^14

energy = 4.556 x 10^-19 J or 2.843 eV

(c) The modern classification of light says that wavelengths between 380–450 nm are violet, however, using Newton's original seven-colour definition, traditionalists would still call 436 nm indigo.