Question

If the energy required to remove an electron from sodium is `8.23xx10^-19 J`, what frequency of light will cause sodium to ionize?

Answer 1

`1.24xx10^15` `"s"^-1`

Explanation:

What we need to do here is convert from energy of a photon to its corresponding wavelength.

To do this, we can use the formula

`ul(E = hf`

where

• `E` is the energy of the photon (given as `8.23xx10^-19` `"J"`)

• `h` is Planck's constant, equal to `6.626xx10^-34` `"J"*"s"`

• `f` is the frequency of the light

We can rearrange the equation to solve for the frequency, `f`:

`f = E/h`

Plugging in known values:

`f = (8.23xx10^-19cancel("J"))/(6.626xx10^-34cancel("J")*"s") = color(red)(ulbar(|stackrel(" ")(" "1.24xx10^15color(white)(l)"s"^-1" ")|)`