Final answer:
The maximum speed of emitted electrons can be calculated using the stopping potential. The work function and the metal can be identified using the stopping potential.
Step-by-step explanation:
When light shines on a metal surface, electrons are emitted in a process called photoelectric effect. The maximum speed of emitted electrons can be calculated using the equation Vm = ((2eU) / m)0.5, where Vm is the maximum speed, e is the charge of an electron, U is the stopping potential, and m is the mass of an electron. For the given stopping potential of 1.25 V, the maximum speed of emitted electrons is approximately 5.42 x 105 m/s.
The work function of a metal can be calculated using the equation φ = eU, where φ is the work function and U is the stopping potential. In this case, the work function is approximately 1.99 eV. The metal can be identified by comparing the calculated work function with the known work functions of different metals.