Monochromatic light with a photon energy of 4.8×10−19 J4.8 \times 10^{-19} \text{ J}4.8×10−19 J is incident on a metal surface. The maximum speed of the photoelectrons released is 4.8×105 m s−14.8 \times 10^5 \text{ m s}^{-1}4.8×105 m s−1.
What is the work function of the metal?
(Take the mass of an electron, me=9.11×10−31 kgm_e = 9.11 \times 10^{-31} \text{ kg}me=9.11×10−31 kg)
2.7×10−19 J2.7 \times 10^{-19} \text{ J}2.7×10−19 J
3.8×10−19 J3.8 \times 10^{-19} \text{ J}3.8×10−19 J
4.8×10−19 J4.8 \times 10^{-19} \text{ J}4.8×10−19 J
5.9×10−19 J5.9 \times 10^{-19} \text{ J}5.9×10−19 J
