How can the value of the constant, 1240, in the Duane-Hunt relation be verified?

[saiyaex]

Homework Statement

Just going over some practice questions, and one of them is:

1. Verify the value of the constant, 1240, in the Duane-Hunt relation.

Homework Equations

E(eV) = 1240/lambda(nm)

The Attempt at a Solution

I know it is used as a quick method in finding how much energy is involved when a molecule absorbs a photon of light. I therefore know how to use it in a question. However, I'm stumped as to verifying the actual value of the constant. Any insight is appreciated!

 

[collinsmark]

Look up the definition of Planck's constant, or more specifically what is called the "Planck relation" or the "Planck–Einstein equation". It relates the energy of a photon to the photon's frequency (or wavelength).

A few other things you may need to know.

• What is the speed of light in a vacuum (in [m/sec])?
• What is Planck's constant (in [J sec])?
• If you know the frequency of a photon, what is the photon's wavelength?
• How many Joules are there in one electron-volt?
• how many nanometers are there in a meter?