Light source having wavelength 331 nm is used to generate photo-electrons whose stopping potential is 0.2 V. The work function of the used metal in the experiment is 10⁻¹⁹ J. The value of is _____. ( h = 6.62 10⁻³⁴ J s, e = 1.6 10⁻¹⁹ C and c = 3 10^8 m/s)

Step-by-step solution

Using Einstein's photoelectric equation: hc = + eV₀ The energy of the incident photon is: E = hc = 6.62 10⁻³⁴ 3 10^8 331 10⁻⁹ E = 19.86 10⁻²⁶ 331 10⁻⁹ = 6 10⁻¹⁹ J The maximum kinetic energy of the photoelectrons is: K_ max = eV₀ = 1.6 10⁻¹⁹ 0.2 = 0.32 10⁻¹⁹ J The work function is: = E - K_ max = 6 10⁻¹⁹ - 0.32 10⁻¹⁹ = 5.68 10⁻¹⁹ J Comparing with 10⁻¹⁹ J, we get = 5.68 . Answer: 5.68