1. What is Stopping Voltage?

Definition: Stopping voltage (V_s) is the minimum voltage needed to stop photoelectrons emitted due to the photoelectric effect.

Purpose: This calculator helps determine the stopping voltage based on photon frequency and material's work function.

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 of electrons, which when divided by electron charge gives the stopping voltage.

3. Importance of Stopping Voltage

Details: Stopping voltage measurement is crucial in quantum physics experiments and helps verify Einstein's photoelectric equation.

4. Using the Calculator

Tips: Enter the photon frequency in Hz and work function in eV. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the work function?
A: The work function is the minimum energy needed to remove an electron from a material's surface.

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., 2.3 eV for potassium, 4.7 eV for copper).

Q4: Why is stopping voltage negative sometimes?
A: If the photon energy is less than the work function, no photoelectrons are emitted (negative result means no emission).

Q5: What's the significance of Planck's constant here?
A: It relates the energy of photons to their frequency in the quantum mechanical relationship E = h×f.