1. What is a Stopping Voltage Calculator?

Definition: This calculator determines the stopping voltage needed to prevent electrons from reaching the anode in the photoelectric effect.

Purpose: It helps physicists and electrical engineers analyze photoelectric experiments and understand electron emission.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( V_s \) — Stopping voltage (Volts, V)
• \( h \) — Planck's constant (4.1357 × 10⁻¹⁵ eV·s)
• \( f \) — Photon frequency (Hertz, Hz)
• \( \phi \) — Work function (eV)
• \( e \) — Electron charge (1.602 × 10⁻¹⁹ C)

Explanation: The photon energy (h×f) minus the work function gives the kinetic energy, which is converted to stopping voltage by dividing by electron charge.

3. Importance of Stopping Voltage Calculation

Details: Accurate stopping voltage calculation is crucial for understanding the photoelectric effect, designing photoelectric devices, and verifying quantum theory.

4. Using the Calculator

Tips: Enter the photon frequency in Hz and work function in eV. Both values must be positive (frequency > 0, work function ≥ 0).

5. Frequently Asked Questions (FAQ)

Q1: What is the physical meaning of stopping voltage?
A: It's the minimum voltage needed to stop the most energetic photoelectrons from reaching the anode.

Q2: How is photon frequency related to wavelength?
A: Frequency (f) = speed of light (c) / wavelength (λ), where c ≈ 3×10⁸ m/s.

Q3: What are typical work function values?
A: Common values range from 2-6 eV (e.g., ~4.5 eV for copper, ~2.3 eV for sodium).

Q4: Why is the result sometimes negative?
A: A negative result means the photon energy is below the work function, so no photoelectric emission occurs.

Q5: How precise are these calculations?
A: Results are theoretical and assume ideal conditions. Real-world factors like surface impurities may affect actual values.