A beam of light, with a wavelength of 4170 Å, is shined on sodium, which has a work function (binding energy) of 4.41 × 10 –19 J. Calculate the kinetic energy and speed of the ejected electron.

Explanation:

Given that,

Wavelength of the light,

Work function of sodium,

The kinetic energy of the ejected electron in terms of work function is given by :

The formula of kinetic energy is given by :

Hence, this is the required solution.

answer: 2×10^-2kg

explanation: density= mass per volume

vol=mass/density

converting to s.i units we have;

3÷1000kg = 0.003

1.5÷100m = 0.15

0.003/0.15 = 0.02kg