Question

What is the energy of a photon with a frequency of 7.00 x 104 s 1? (h 6.626x 10 34J.s) J

Answer 1

We have the formula for energy of photon

E = hc / $\lambda$

Where

h = Planks constant = 6.626 $\times$ 10^-34 J.s

c = speed of light = 3.0 $\times$ 10⁸ m/s

$\lambda$ = wavelength of radiation

Lets calculate $\lambda$ with given frequency

we know that

wavelength $\lambda$ = speed of light (c) / Frequency (v)

Frequency = 7.0 $\times$ 10¹⁴ s^-1

then

wavelength $\lambda$ =   3.0 $\times$ 10⁸ m/s / 7.0 $\times$ 10¹⁴ s^-1 = 4.29 $\times$ 10^-7 m

Now

E = hc / $\lambda$

= 6.626 $\times$ 10^-34 J.s  $\times$ 3.0 $\times$ 10⁸ m/s / 4.29 $\times$ 10^-7 m

= 4.63 $\times$ 10^-19 J

So our answer is 4.63 $\times$ 10^-19 J