Final answer:
The student's question asks for the cutoff wavelength and threshold frequency for the photoelectric effect using the work function of molybdenum. To solve for these values, convert the work function from electron volts to joules and use formulas that incorporate Planck's constant and the speed of light.
Step-by-step explanation:
The student's question involves the calculation of the cutoff wavelength and threshold frequency for the photoelectric effect given the work function of molybdenum, which is 4.2 eV. To find the cutoff wavelength (λc) and threshold frequency (f0), we can use the equations:
λc = ίc / W and f0 = W / h,
where ίc is the speed of light in vacuum, W is the work function of the material in joules, h is Planck's constant, and eV is the electronvolt unit. However, we need to first convert the work function from eV to joules (J) using the conversion 1 eV = 1.602 × 10-19 J.
The calculation steps are as follows:
- Convert the work function to joules: W = 4.2 eV × 1.602 × 10-19 J/eV.
- Calculate the cutoff wavelength using ίc = 3.00 × 108 m/s and the converted W.
- Calculate the threshold frequency using W and h = 6.626 × 10-34 J·s.
The values obtained from these calculations present the minimum energy required in the form of a photon to eject an electron from the molybdenum surface, and no photoelectric effect would occur if the incident light has a wavelength longer than λc or a frequency lower than f0.