Question

1.An aluminum cathode has a work function Φ=4.1eV. A stopping voltage Vs=1.7 V is applied between the anode and cathode. What is the maximum wavelength of the photon necessary to observe a current across the photoelectric tube? (8pts) [Answer in nm]

2.In an ion beam experiment, He+ ions are accelerated between two electrodes in a vacuum tube to generate a beam of high-energy ions. The ions reach kinetic energy Ek = 4·10-19 Joules and their mass is m=6.65·10-27 kg. What is the momentum p of these accelerated ions? (5 pts) [Answer in kg·m·s-1 ]

3.In a similar experiment Ar+ ions are accelerated to generate an argon ion beam. The mass of the Ar+ ions is m=6.63 × 10-26 kg and they reach kinetic energy Ek=5 × 10-19 Joules. These particles are light and have high velocity therefore they can be subjected to quantum effects. What is the wavelength of these Ar+ ion. (8 pts) [Answer in m]

4.A photon of wavelength 238 nm extracts an electron from an iron electrode (Φ=4.31eV), what is the wavelength of this electron? Remember electrons are also particles subjected to quantum effects. (8pts) [Answer in nm]

Answer 1