Physics 123, Spring, 2005

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Overview of the coursePrinciples of geometric
optics

• Physics 123, Spring, 2005

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Introduction

• Instructor Prof. Regina Demina
• Office BL 313
• Phone [phone]
• Email regina_at_pas.rochester.edu
• Office hour Mon 4-5 pm

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Novosibirsk
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Objective of the course

• thorough understanding of the basic physics
  concepts
• ability to use them in applications

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Sources

• Text book
• Physics for Scientists and Engineers, Volume
  II
• Third Edition
• by Douglas C. Giancoli

• Class web site /www.pas.rochester.edu/regina/PHY1
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• Lecture notes
• Homework assignments, numeric answers, solutions
• Equation sheets for tests, test solutions
• Important dates and links

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Recitations and Homework

• Solving problems systematically is important.
• Difference with PHY122 no more workshops?
  recitations
• Recitations will cover material through the
  Wednesday lecture.
• Participation in recitations will count 10 of
  your final grade. Grade assigned by your TA.
• Recitations start the week of 1/18, sign up will
  be open on Thursday 01/13 https//spider.pas.roch
  ester.edu/signup/PHY-123-S05/
• Homework is due in recitation class.
• Homework problems 10 of your final grade.

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One hour exams

• There will be two one-hour exams during the
  semester.
• Both will count.
• There will be no makeup exam.
• Exams will be given in Wednesday lecture class
  shown in the schedule. Exam dates are subject to
  change. I will notify you by email in case of
  change.
• You can bring a calculator, a pencil and a ruler.
• 40 of your grade.

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Final Exam

• Tuesday, May 3, 830 am (sorry!)
• Final exam is based on the entire course PHY123.
• Last homework will be based on the entire course
  to give you more time to prepare for the final.
  It will not be graded.
• 30 of the final grade

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Equation sheets

• No notes or equation sheets may be brought to
  exams.
• However, a sheet of useful equations will be
  provided during the test. You can view these
  sheets in advance, will be linked from course
  schedule on the web.
• Please note that past experience has shown that
  having equations available does not guarantee
  success -- understanding is the key.

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Labs

• The laboratory is a required and integrated part
  of the course.
• A passing grade in laboratory is required to pass
  the course 10 of the grade
• Lab manuals and sign up are available on the web
  http//web.pas.rochester.edu/physlabs/home.shtml
  
• See the lab manual for rules and grading
  procedures.
• Start sign up this week (you will be notified by
  email, but you need to be registered for lab
  class!!)
• Important There is a short homework (in manuals)
  due at the beginning of each lab class (even the
  1st one!!!) You will not be allowed to start your
  lab without this homework.

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Grading

• Workshops 10
• Homework 10
• Hour Exams 40
• Final Exam 30
• Laboratory 10
• Total 100
• 90 or above A 88-89.9 A- 85-87.9 B
• 80 - 85 B 78-79.9 B- 75-77.9 C
• 70 - 75 C 68-69.9 C- 65-67.9 D
• 60 - 65 D
• Under 60 F

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Phys 121?123

• Phys 121
• how do objects move (kinematics)
• Why do objects move (dynamics forces)
• One true (fundamental) force gravity
• First step into the micro world kinetic theory
• Phys 122
• Two more true forces electricity and magnetism
• Unification EM waves light
• Phys 123
• More detailed study of light
• Geometric optics? wave properties ? particle
  properties ? Quantum mechanics (lasers) ?
  space-time properties
• Deeper into the structure of matter atomic
  structure
• Nuclear structure, elementary particles
• Way out in space - cosmology

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Principles of geometric optics
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Concepts

• Ray model of light
• Image formation
• Reflection
• Refraction
• Dispersion
• Total internal reflection

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EM waves

• c speed of light (m/s)
• f frequency (Hz1/s)
• l wavelength (m)

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Ray model of light

• Light is an EM wave ?diffraction (go around
  obstacles)
• This happens on microscopic scale
• In everyday life we use straight line
  approximation for light propagation Ray model
  of light ? geometric optics
• We infer positions of objects assuming light
  travels in straight lines.

Geometry is important, Bring ruler and
pencil, make good pictures!!!
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Reflection

• We see objects because
• They emit light (Sun, light bulb)
• They reflect light (Moon, table)
• angle of incidence angle of reflection
• qiqr

Rough surface Polished surface.
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Formation of image

• Eye assumes light propagates in straight lines ?
  image (rays of light crossing) is formed behind
  the mirror
• do distance to object
• di distance to image
• For plane mirror
• do di

If light actually goes through the place where
image is formed ? real image
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Speed of light in medium

• Speed of light in vacuum
• c3.0x108m/s
• Speed of light in media
• vltc
• Index of refraction
• nc/v gt1.0

From table 33-1 Vacuum n1.00 Air
n1.0003 Water n1.33 Diamond n2.42
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Refraction

• The front is slowing down

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Refraction, Snells law
Bend toward normal Bend away from normal
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Image formation

• Eye still assumes light propagates in straight
  lines ? optical illusions
• Image is shifted
• Pool appears shallower

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What if n depends on l?

• If n depends on l ? angle of refraction depends
  on l
• n(red)ltn(green)

• A-red, B-green
• B- red, A-green

A
B
Dispersion This is why rainbow occurs
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Total internal reflection
For qgtqc - total internal reflection no light
come out all light is reflected Fiber
optics Necessary condition from thick to thin
media
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