Question

A certain shade of blue has a frequency of 7.02 × 1014 Hz. What is the energy of exactly one photon of this light?

Answer 1

Answer : The energy of one photon is $4.65\times 10^{-19}J$

Explanation : Given,

Frequency of blue light = $7.02\times 10^{14}Hz=7.02\times 10^{14}s^{-1}$

Formula used :

$E=h\nu$

where,

$\nu$ = frequency of blue light

h = Planck's constant = $6.626\times 10^{-34}Js$

E = energy of one photon = ?

Now put all the given values in the above formula, we get:

$E=(6.626\times 10^{-34}Js)\times (7.02\times 10^{14}s^{-1})$

$E=4.65\times 10^{-19}J$

Therefore, the energy of one photon is $4.65\times 10^{-19}J$

Answer 2

 The energy (E) per photon is expressed by Planck's equation: E = hf, where f is 
the frequency and h is Planck's constant, experimentally determined to be 
6.625 * 10**-34 joule-seconds. So to find E, we multiply h by the frequency 
and obtain E = hf = (6.625 * 10**-34)(7.0 * 10**14) = 46.375 * 10**-20 joule 
or in standard notation, E = 4.6375 * 10**-19 joule per photon. 

Hope this answers your question.Sorry if I calculated wrong.