Concepts Of Physics MCQ Edition [Volume 2]PhysicsPhotoelectric Effect and Wave–Particle Duality
In a photoelectric effect experiment, the stopping potential is measured for monochromatic light beams of varying wavelengths. Determine the work function of the emitter from the experimental data. wavelength (nm) 350 400 450 500 550 stopping potential (V) 1.45 1.00 0.66 0.38 0.16
Options
- A2.15 eV
- B1.08 eV
- C3.15 eV
- D4.30 eV
Correct answer
A. 2.15 eV
Step-by-step solution
According to Einstein's photoelectric equation: eV_s = hc - where V_s is the stopping potential, is the wavelength of incident light, and is the work function of the material. Using the standard value hc 1240 eV nm , we can calculate the work function for the given data points. For = 400 nm and V_s = 1.00 V : = 1240 400 - 1.00 = 3.10 - 1.00 = 2.10 eV For = 500 nm and V_s = 0.38 V : = 1240 500 - 0.38 = 2.48 - 0.38 = 2.10 eV The calculated work function is approximately 2.10 eV . Among the given choices, the closest