Stopping Voltage Calculator

The stopping voltage in a photoelectric experiment is the minimum voltage needed to stop the most energetic photoelectrons emitted from a metal surface. This concept is pivotal in understanding the photoelectric effect, where light causes an electron to be ejected from a material.

Historical Background

The photoelectric effect, first observed by Heinrich Hertz in 1887 and later explained by Albert Einstein in 1905, demonstrates the particle nature of light. Einstein's explanation, which earned him the Nobel Prize in Physics in 1921, uses the concept of photons to describe how light of sufficient frequency can eject electrons from a material. The stopping voltage is a direct measurement of the maximum kinetic energy of these photoelectrons.

Calculation Formula

The formula for calculating the stopping voltage (\(SV\)) is given by:

\[ SV = \frac{KE}{e} \]

where:

• \(SV\) is the stopping voltage in volts (\(V\)),
• \(KE\) is the maximum kinetic energy of the photoelectrons in joules (\(J\)),
• \(e\) is the elementary charge of an electron in coulombs (\(C\)), approximately \(1.602176634 \times 10^{-19} C\).

Example Calculation

For a photoelectron with a maximum kinetic energy of \(3.2 \times 10^{-19} J\):

\[ SV = \frac{3.2 \times 10^{-19}}{1.602176634 \times 10^{-19}} \approx 2 V \]

Importance and Usage Scenarios

The stopping voltage is crucial in experiments involving the photoelectric effect, enabling researchers to calculate the maximum kinetic energy of ejected electrons. This measurement is fundamental in the study of electronic properties of materials, semiconductor physics, and the development of devices like photodiodes and solar cells.

Common FAQs

1. What is the photoelectric effect?

   • The photoelectric effect is the emission of electrons from a material when light of sufficient frequency shines on it.

2. How does stopping voltage relate to the photoelectric effect?

   • The stopping voltage is used to measure the maximum kinetic energy of electrons ejected by the photoelectric effect, demonstrating the quantized nature of light.

3. Why is the electron charge constant in the formula?

   • The charge of an electron is a fundamental physical constant, representing the quantity of electric charge carried by a single electron.

This calculator streamlines the process of calculating the stopping voltage, making it accessible for educational purposes, research, and practical applications in physics and engineering.