The work function of tungsten is 4.50 eV - Leaving Cert Physics - Question (h) - 2014

Rearranging the equation to solve for the kinetic energy:

$KE_{electron} = E_{photon} - Work \, function$ Substituting the values:

$KE_{electron} = 5.85 \, eV - 4.50 \, eV$ $KE_{electron} = 1.35 \, eV$

To convert the kinetic energy from electronvolts to joules, we use the conversion factor:

$1 \, eV = 1.6 imes 10^{-19} \, J$

Thus, the kinetic energy in joules is:

$KE_{electron} = 1.35 \, eV \times 1.6 imes 10^{-19} \, J/eV = 2.16 \times 10^{-19} \, J$

The maximum kinetic energy of the electron ejected from the tungsten surface is therefore:

1.35 eV (or 2.16 x 10^-19 J) after conversion.