200k views
1 vote
Neon discharge tubes emit a light with a wavelength of 600. Nm that appears deep orange to the human eye. How many photons of this electromagnetic radiation amount to 250. J of energy?

User Nayra
by
7.2k points

1 Answer

5 votes

Answer:


7.53\cdot 10^(20)

Step-by-step explanation:

First of all, we need to calculate the energy of one photon with wavelength 600 nm. The energy of each photon is given by


E=(hc)/(\lambda)

where


h=6.63\cdot 10^(-34) Js is the Planck's constant


c=3\cdot 10^8 m/s is the speed of light


\lambda=600 nm=6\cdot 10^(-7) m is the wavelength of the light

Substituting numbers into the formula, we find


E_1=((6.63\cdot 10^(-34)Js)(3\cdot 10^8 m/s))/(6\cdot 10^(-7) m)=3.32\cdot 10^(-19) J

Now to find the number of photons, we simply divide the total energy (250 J) by the energy of one photon:


n=(E)/(E_1)=(250 J)/(3.32\cdot 10^(-19) J)=7.53\cdot 10^(20)

User Zachguo
by
6.9k points