Photoelectrons are released when 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 work function of the surface is 2.3 eV2.3 \text{ eV}2.3 eV.
What is the maximum speed of the photoelectrons as they leave the surface?
7.4×105 m s−17.4 \times 10^5 \text{ m s}^{-1}7.4×105 m s−1
5.0×105 m s−15.0 \times 10^5 \text{ m s}^{-1}5.0×105 m s−1
3.5×105 m s−13.5 \times 10^5 \text{ m s}^{-1}3.5×105 m s−1
1.0×106 m s−11.0 \times 10^6 \text{ m s}^{-1}1.0×106 m s−1
