What is the number of photons of light with a wavelength of 4000 pm that provide IJ of energy?
Answers
Energy (E) of a photon =
Where, h is the plank’s constant =6.626 X 10-34 Js
c is the velocity of light in vacuum = 3 X 108 ms-1
Is the wavelength of light = 4000 x 10-12m
= 4 X 10-9 m
Putting the values in the relation E, we get
E =4.9695 X 10-19 J
Therefore, Energy of the photon is 4.97 X 10-19 J.
Now, 4.965 X 10-16 J is the energy of one photon.
So, 1 J will be the energy of = J
= 2.014 X 1015 photons.
Answer:
Explanation:
Energy of one photon (E) = hv
Energy of ‘n’ photons (En) = nhv => n = Enλ/hc
Where λ is the wavelength of the photons:
= 4000 pm = 4000 * 10^-12 meter
c denotes the speed of light in vacuum = 3 * 10^8 m/sec
h is plancks constant whose value = 6.26 * 10^-34 j/sec
Substituting these values in the expression for n:
n = 1 * 4000 * 10^-12 /( 6.26 * 10^-34)(3*10^5)
= 2.012 * 10^16
Hence, the number of photons with a wavelength of 4000 pm and energy of 1 J are 2.012 * 10^16.