Question

A photon of light of wavelength 470 nam falls on a metal surface. As a result photons are ejected with a velocity of 6.4 x 10^4 m/s. Find the kinetic energy of emitted photoelectrons

Answer 1

$\frac{1}{2} \times 9.1 \times {10}^{ - 31} \times ( {6.4 \times {10}^{4} })^{2}$
equals to
$1.863 \times {10}^{ - 21}$