Physics 7 E Prof D Casper Admin Midterms

Physics 7 E Prof. D. Casper

Admin • Midterms to be returned in Thursday’s discussion sections • Chapter 16 HW is due Thursday • Reading • Wednesday: Chapter 32. 1 – 32. 3 • Friday: Chapter 32. 3 – 32. 5 • Monday: Chapter 33. 1 – 33. 2

Doppler Effect: Moving Listener •

Q 16. 8 On a day when there is no wind, you are moving toward a stationary source of sound waves. Compared to what you would hear if you were not moving, the sound that you hear has A. a higher frequency and a shorter wavelength. B. the same frequency and a shorter wavelength. C. a higher frequency and the same wavelength. D. the same frequency and the same wavelength.

A 16. 8 On a day when there is no wind, you are moving toward a stationary source of sound waves. Compared to what you would hear if you were not moving, the sound that you hear has A. a higher frequency and a shorter wavelength. B. the same frequency and a shorter wavelength. C. a higher frequency and the same wavelength. D. the same frequency and the same wavelength.

Doppler Effect: Moving Source • Positive velocity means in direction from L to S!

Q 16. 9 On a day when there is no wind, you are at rest and a source of sound waves is moving toward you. Compared to what you would hear if the source were not moving, the sound that you hear has A. a higher frequency and a shorter wavelength. B. the same frequency and a shorter wavelength. C. a higher frequency and the same wavelength. D. the same frequency and the same wavelength.

A 16. 9 On a day when there is no wind, you are at rest and a source of sound waves is moving toward you. Compared to what you would hear if the source were not moving, the sound that you hear has A. a higher frequency and a shorter wavelength. B. the same frequency and a shorter wavelength. C. a higher frequency and the same wavelength. D. the same frequency and the same wavelength.

The Doppler Effect and Reflections •

Complicated Example with Reflection •

Bat Example (1) •

Bat Example (2) •

Electromagnetic Waves In this chapter, you should learn: • Why there are both electric and magnetic fields in a light wave • How the speed of light is related to the fundamental constants of electricity and magnetism • How to describe the propagation of a sinusoidal electromagnetic wave • What determines the amount of power carried by an electromagnetic wave • How to describe standing electromagnetic waves

Maxwell’s Equations (#1 and #2) •

Maxwell’s Equations (#3) •

Maxwell’s Equations (#4) •

Electromagnetic Waves An oscillating or accelerating electric charge will radiate energy as a disturbance in the electric (and magnetic) fields According to Maxwell’s equations, such a disturbance in the fields propagates with the speed of light…because it is light! The expected behavior was confirmed experimentally by Heinrich Hertz

The Electromagnetic Spectrum Visible light spans a very narrow band of frequencies, compared to full spectrum of electromagnetic radiation

Properties of Electromagnetic Waves (in vacuum) •

Plane Waves •

Sinusoidal Electromagnetic Waves