PPT Slide
- As an object is heated, it begins to emit visible light, first as a red glow, then orange, then white light.
- Attempts to use electromagnetic theory to predict wavelengths of the emitted light failed.
- Max Planck proposed that the hot, glowing object could emit (or absorb) only certain amounts of energy:
-where E is the radiation energy, _ is its frequency, n is a positive integer called a quantum number, and h is Planck’s constant.
- With E in joules (J) and frequency in s –1 , h has units of J•s:
Notes: