CEM 141 EXAM 2 QUESTIONS & ANSWERS

CEM 141 EXAM 2 QUESTIONS & ANSWERS


1. To understand atomic structure we need to understand
electromagnetic radiation.: What is electromagnetic radiation?
What are some examples that you encounter?

2. Examples of electromagnetic radiation: •Radio waves
• Microwaves
• Infrared
• Visible
• Ultraviolet
• X-rays
• Gamma rays


How do we characterize electromagnetic radiation? What is ditterent about radio waves and X-rays?

3. Two models are used to describe the behavior or light (electromagnetic
radiation). What is light?: A wave and a particle
4. Electromagnetic radiation: •Wavelength, λ (m) - distance from peak to peak
• Frequency, v (Hz=1/s) - number of wave fronts per sec
• c=λ x v
-Where c=velocity of light (3.00 x 10^8 m (1/s))
• Amplitude - height of peaks (intensity)
• Energy - increases as frequency increases (and wavelength decreases)

5. The Electromagnetic Spectrum: Note: Scale on the Spectrum is a log Scale


• Lets say we have 2 objects 1 m apart (10^0 m)...
• How far apart would 2 objects be that were 10^1 m apart?


,-10 m
• How far apart would 2 objects be that were 10^2 m apart?
-100 m
• How far apart would 2 objects be that were 10^3 m apart?
-1000 m

6. Relative Wavelength Sizes:






,7. 1 nm: 1 x 10^-9 m
8. Properties of Wave Diffraction:




9. Properties of Wave Interference:




10. Properties of Waves: Diffraction Patterns:






, 11. Which has longest wavelength?
A. X-rays
B. Visible
C. Infrared: C. Infrared
12. Which has highest frequency?
A. X-rays
B. Visible
C. Infrared: A. X-rays