WAEC - Physics (2013 - No. 37)
The work function of a metal is 2.56 x 10-19J. Calculate the frequency of a photon whose energy is required to eject from the metal an electron with kinetic energy of 3.0ev. [1 eV = 1.6 x 10-19J, h = 6.6 x 10-34Js]
5.56 x 1019Hz
1.66 x 1019Hz
1.12 x 1015Hz
8.42 x 1014Hz
Vysvetlenie
F = \(\frac{K.E + Wo}{h}\)
= \(\frac{3.0 \times 1.6 \times 10^{-19} + 2.56 \times 106{-19}}{6.6 \times 106{-34}}\)
- 1.12 x 10-15HZ
= \(\frac{3.0 \times 1.6 \times 10^{-19} + 2.56 \times 106{-19}}{6.6 \times 106{-34}}\)
- 1.12 x 10-15HZ