Question

Mercury inside of a spectrum tube gives off a blue light when electricity is passed through. What is the energy of this blue light if a photon released has a wavelength of 450 nm?

a) 4.41 x 10^-19 J
b) 2.21 x 10^-19 J
c) 8.82 x 10^-19 J
d) 1.10 x 10^-18 J

Answer 1

The energy of a photon with a wavelength of 450 nm is calculated using the formula E = (hc) / λ, resulting in an energy of 4.41 x 10^-19 J, which is choice a).

Step-by-step explanation:

To calculate the energy of a photon with a wavelength of 450 nm, one would use the formula E = (hc) / λ, where h is Planck's constant (6.626 x 10-34 J·s), c is the speed of light in a vacuum (3 x 108 m/s), and λ is the wavelength of the photon in meters.

Converting the wavelength from nanometers to meters (1 nm = 1 x 10-9 m), we get:

λ = 450 nm = 450 x 10-9 m

Now we can calculate the energy:

E = (6.626 x 10-34 J·s)(3 x 108 m/s) / (450 x 10-9 m)

E = 4.41 x 10-19 J

Thus, the energy of the blue light emitted by mercury when a photon is released with a wavelength of 450 nm is 4.41 x 10-19 J.