Introduction

Readings
Chapter 18, pages 407-413, of Spears and Zollman
Activity 2, Solids & Light, VQM Activities manual

Homework
S&Z Chapter 18 C2; C3a, c, d; C4a

For problem C3 Sodium energies in eV are:
-1.10 eV
-1.40 eV
-1.60 eV
-1.90 eV
-3.00 eV
-5.10 eV

For problem C4 the lowest energy in hydrogen is -13.6 eV

In this activity (Corresponding to Activity 2 in your Visual Quantum Mechanics Activities manual) we will continue to investigate the properties of LEDs and the incandescent lamp by observing and exploring the light patterns emitted by some devices.

In the previous tutorial we examined the light emitted by LEDs and incandescent lamps. Both of these light sources are examples of light emission from solids. In solids the interaction between closely packed atoms makes it difficult to understand what is going on. Thus, we will begin with gases where the component atoms are far away from each other; study how they emit light and then work back to a situation where atoms are close together.

In addition to the incandescent lamp and LEDs we will investigate gas lamps. These gas lamps, which are somewhat similar to fluorescent tubes, will emit light. By investigating this light we will be able to build a conceptual model of how gas atoms emit light. We will then extend this model to the closely spaced atoms in a solid and, thus, to LEDs.