Experiencing Bluetooth® issues with Go Direct® sensors on Chromebooks? Get help here.

Experiments​

Introduction

The energy of a photon is related to its frequency by the equation E = hf, where h is Planck’s constant. By determining the potential required to excite an LED to emit light, you can estimate the energy of the photons emitted. Using a spectrometer, you can measure the peak wavelength of the emitted light; from this, the frequency can be calculated. Performing this analysis for a number of LEDs will enable you to obtain a reasonable approximation of the value of Planck’s constant.

Objectives

In this experiment, you will

  • Collect and analyze current vs. potential data to estimate the energy required to excite a number of LEDs.
  • Use a spectrometer to determine the wavelength of the peak output of each LED.
  • Determine a value for Planck’s constant from an analysis of the energy and frequency of the light emitted by a number of LEDs.

Ready to Experiment?

Ask an Expert

Get answers to your questions about how to teach this experiment with our support team.

Purchase the Lab Book

This experiment is #22 of Advanced Physics with Vernier — Beyond Mechanics. The experiment in the book includes student instructions as well as instructor information for set up, helpful hints, and sample graphs and data.

Learn More

SAVE/SHARE YOUR CART