Physics of AstronomySpring 2006

Astronomy & Astrophysics

Electromagnetism

Seminar: Cosmology & Journals

Your research

Today: short course on LIGHT

When shall we have weekly research reports? Mondays after HW session?

Seminar

Electromagnetism

• Giancoli = primary source

• New! Workshop Physics Module 4 by Laws (Dickinson) on reserve in Library

• Copy or order Workshop Physics

Light (today)Potentials (next week)Circuits through Maxwell’s equations

□ Look at SYLLABUS together…

Light

Ch.33 Reflection & Refraction

Ch.34 Lenses & optical instruments

Ch.35 Interference

Ch.36 Diffraction & Polarization

Hitting the high points….

Ch.33 Reflection

Images formed in mirrors

1 1 1

object imaged d f

Refraction: v = c/n; n1sin1 = n2sin2

Q.13

Refraction

Total internal reflection

Ch.34 Lenses & optical instruments

1 1 1

object imaged d f

Object far from converging lens forms real image near focal point.

Object close to converging lens forms virtual image.

Combinations of lenses

(1) Find location of Image 1 → (2) Let this be Object 2 → Find Image 2

Simple camera and human eye

Corrective lenses

Magnifying glass

Telescope

Ch.35 Interference

Huyghen’s principle

Every point on a wave front can be considered as a source of tiny wavelets that spread our in the forward direction at the speed of the wave itself.

Huyghens explains refraction

Interference – Young’s double-slit experiment

□ First, PREDICT PATTERNS if light is PARTICLES or WAVES

Interference – theoretical explanation

Interference bright spots

sind m

Ch.36 Diffraction & Polarization

Diffraction through a single slit

sina m

Diffraction DARK spots at

Diffraction through a double slit

Diffraction grating

Resolution limits

1.22

D

Polarization

Polarization by reflection

2

1

tan p

n

n