The given hypothesis is a classical theory which tries to explain why a light bulb emits light. It is classical because it ignores the wave-like properties of atoms.
Hypothesis 1 Incandescent light comes from a tungsten filament encased in a glass bulb.
1. Electric current passes through the tungsten filament and heats it up.
2. Tungsten atoms vibrate randomly when heated. They move more when they are hotter.
Question 1. Use the fact that atoms are made of charged protons and electrons to explain why the random vibration produces light.
Question 2. Consider an experiment where you produce waves on a string by moving one end up and down with your hand. What is the relationship between the frequency of your hand (ie. the number of times per second you move your hand up and down) and the frequency of the wave on the string?
Question 3. What do you think is the relationship between the frequency of atomic vibration in the tungsten filament and the frequency of emitted light? Based on this hypothesis, what frequencies should be present in the light emitted by the filament?
Question 4. If the atoms are hotter, then we can expect that they will move faster and farther. What do you think that this would do to the brightness of the light? What about the color of the light?
Question 5. What is the energy transformation which occurs when light is produced? In other words, where does the energy for the light come from? Give answers in terms of both macroscopic and microscopic energies.