ELECTROMAGNETIC WAVES Light etc PHY 2054 Spring 2011
- Slides: 25
ELECTROMAGNETIC WAVES Light etc. PHY 2054 Spring 2011 April 13, 2011
TITLE • Today we start the study of electromagnetic waves and LIGHT as in “let there be”. • This will lead to a discussion of – Polarization – Mirrors – Lenses – Perhaps interference and diffraction • There available experiments for each of these. Not sure how far we will get but we will get there quickly!
April 2011 Time is on the move! Sunday Monday Tuesday Wednesday Thursday Friday Saturday 1 2 3 4 Complete Induction 5 6 AC 7 8 AC Quiz? 9 10 11 COMPLETE AC EXPT 12 13 OPTICS 14 15 OPTICS 16 17 18 EXAM #3 (No Optics) 19 20 OPTICS 21 22 OPTICS 23 24 25 (LAST LASS) OPTICS 26 27 28 29 30 FINAL HPA 119 9: 00 AM EM Waves POLARIZATION Quiz
WHERE IS THE FINAL EXAM? ?
What’s on Exam #3? Questions! 5 Multiple choice questions Three problems covering Magnetism Induction AC Circuits
A sound wave A. B. C. D. is a transverse wave is a longitudinal wave travels at the speed of light has a color spectrum
Sound Waves
Light James Clerk Maxwell (1831 - 1879) was a genius who studied the properties of Electricity and Magnetism. He took a mathematical approach. He published his first scientific paper when he was 15 years old. The four mathematical equations Maxwell produced are ranked with Sir Isaac Newton's laws of motion and Albert Einstein's theory of relativity as the most fundamental contributions to (“classical” )physics. Maxwell’s equations predicted that the electric field and the magnetic field could propagate through empty space. The calculated velocity of these waves turned out to match the speed of light to a very close precision. It was later demonstrated that these waves were, in fact, light waves.
Maxwell’s Equations Gauss’s Law No Mag Poles!! Faraday’s Law Ampere’s Law Displacement Current
Which way is the electric field at P pointing? A B C D E P Left Right Up Down In/Out
Electromagnetic Wave Generation
There is also a current here so there is one of those B things.
Both Together
Propagation The electric and magnetic fields are predicted (and verified) to be perpendicular to each other. The propagation velocity is found to be “c”, the speed of light in a vacuum. of Light c=3 x 108 m/sec. Maxwell calculated that the speed of light in a vacuum to be
Propagation of Light l Since the E and B fields (vectors) are perpendicular to the direction of propagation, the wave is said to be TANSVERSE. Because of this fact, the light wave can be “polarized” The wavelength l of the wave is shown in the diagram. The product of the frequency and the wavelength is c so we see that light can come in different wavelengths (c is a constant)
Waving Along
Sir Isaac
The Electromagnetic Spectrum
Polarization
Polarization Polarized Unpolarized
Changing It Around
Crossed Polarizer's can Transmit light!
Big Money!
Today’s Experiment Polarized Light Read the material at the beginning of the experiment that we haven’t covered Don’t read what we covered today Do the experiment Next time the math!
Get a Blue Box and get to work!!! OPTICS STUFF
- Light waves are transverse waves true or false
- Mechanical and electromagnetic waves
- Mechanical and electromagnetic waves similarities
- Difference between mechanical and electromagnetic waves
- What do all waves transmit
- Difference between matter waves and electromagnetic waves
- Mechanical waves and electromagnetic waves similarities
- Mechanical vs electromagnetic
- 2054
- Light light light chapter 23
- Into the light chapter 22
- Light light light chapter 22
- Concept of electromagnetic waves
- Electromagnetic waves in water
- Electromagnetic energy def
- Em wave energy density
- Electromagnetic spectrum
- Power of electromagnetic waves
- Electromagnetic waves template
- Energy of em wave
- Energy carried by electromagnetic waves
- Radio waves microwaves song
- Electromagnetic waves frequency
- What type of electromagnetic waves cause sunburns? *
- Electromagnetic waves characteristics
- Wavelength formula electromagnetic wave