PHYS 102 1st Edition Lecture 22Outline of Last Lecture I. Calculating Induced VoltageII. Recap of Sample Exam 2Outline of Current Lecture III. Electromagnetic WavesIV. Mechanical WavesV. Properties of Mechanical WavesCurrent LectureIII. Electromagnetic WavesA. Definition: they can exist in a medium or without a medium (in a vacuum, like space); such as: light, laser, x-ray, radio waves, radar, microwave, etc. B. Wave = ray = radiation IV. Mechanical WavesA. Mechanical waves travel only in a medium, whereas electromagnetic waves travel in a medium and in a vacuum. B. Maxwell theory: Electric field (E) and magnetic field (B) are so related that they can move together in space or a medium as Electromagnetic waves. In other words, E B. E B are both to wave propagation (speed v called C in vacuum) E/B = C (speed of a wave in a vacuum) If you have current in wire is there a magnetic field? Yes, if you change E you change B. We need AC current (not DC current) to produce Electromagnetic waves. VI. Properties of Mechanical Waves These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.A. At home, f = 55 Hz Cell phone, f = 2 billion Hz Microwave oven, f = 2.45 billion Hz Derive: = (v/f) ; where is wavelength, v is wave speed, and f is frequency Distance = speed X time Where f is highest, is lowest… and vise versa. Gamma rays have the highest frequency, and radio waves have the highest wavelength. In terms of frequency: Gamma rays > X-rays > Ultraviolet rays > Visible light > Infrared light > Microwaves > Radio waves In terms of wavelength: Radio waves > Microwaves > Infrared light > Visible light > Ultraviolet rays > X-rays > Gamma rays E = hf ; where E is the energy of the wave, h is Plank’s constant, and f is the frequency. Laser stands for light amplification simulated emission
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