If the energy required to remove an electron from sodium is #8.23*10^-19# #J#,, what frequency of light will cause sodium to ionize?

1 Answer
Sep 15, 2016

The frequency is #1.25 × 10^15color(white)(l) "Hz"#.

Explanation:

The formula for the energy of a quantum of light is

#color(blue)(bar(ul(|color(white)(a/a) E = hfcolor(white)(a/a)|)))" "#

where

#E# = energy
#h# = Planck's constant
#f# = frequency

We can rearrange the formula to get

#f = E/h#

#f = (8.23 × 10^"-19" color(red)(cancel(color(black)("J"))))/(6.626 × 10^"-34" color(red)(cancel(color(black)("J")))·"s") = 1.25 × 10^15color(white)(l) "s"^"-1" = 1.25 × 10^15color(white)(l) "Hz"#