Concepts Of Physics MCQ Edition [Volume 2]PhysicsPhotoelectric Effect and Wave–Particle Duality
The figure displays the plot of the stopping potential versus the frequency of the light used in an experiment on the photoelectric effect. Determine the ratio h/e .
Options
- A8.28 10⁻¹⁵ V s
- B1.656 10⁻¹⁵ V s
- C4.14 10⁻¹⁵ V s
- D4.14 10⁻¹⁴ V s
Correct answer
C. 4.14 10⁻¹⁵ V s
Step-by-step solution
According to Einstein's photoelectric equation, eV = h - V = ( h e ) - e The graph of stopping potential V versus frequency is a straight line with slope equal to h e . From the given graph, we can take two points: ( ₁, V₁) = (1 10¹⁴ Hz , 0 V ) and ( ₂, V₂) = (5 10¹⁴ Hz , 1.656 V ) . Slope = V₂ - V₁ ₂ - ₁ h e = 1.656 - 0 (5 - 1) 10¹⁴ h e = 1.656 4 10¹⁴ h e = 0.414 10⁻¹⁴ V s h e = 4.14 10⁻¹⁵ V s