Question

In Einstein's explanation of the photoelectric effect, he guessed that light—electromagnetic waves—can be thought of as being made up of particles he called "photon", with each particle having energy E = h f , where h is Planck's constant ( h = 6.626 × 10 − 34 J ⋅ s ) and f is the frequency of light. Compute the energy of a single photon associated with following electromagnetic waves.

The energy of photon for a 97-MHz FM radio wave is_____________ × 10 − 25 J .

The energy of photon for a 530-nm visible light is_____________ × 10 − 18 J .

The energy of photon for a 120-nm ultraviolet radiation is______________ × 10 − 18 J .

Answer 1

Energy E = hf

where h is the Plank's constant = Js

and f is the frequency.

(a) f = 97MHz = Hz

E = hf = = =

(b) Wavelength

we have, frequency

where c is the velocity of light =

Therefore , E = hf =

=

=

(c)

Energy ,