Lecture 20
April 1, 2010
Chapter 33
Electromagnetic Waves
Fundamental concepts and the properties of electromagnetic waves
33- 1
Maxwells Rainbow
The wavelength/frequency range in which electromagnetic (EM) waves (light) are visible is only a tiny fractio
Lecture 22
April 8, 2010
Chapter 33 continued
Electromagnetic Waves - II
Fundamental concepts and the properties of electromagnetic waves
33- 1
Histogram (distribution) of HT 2 grades
30
Class average = 82
25
Class mean = 83
20
15
10
5
0 36 40 44 48 52 56
Lecture-22 treated: Refraction by Wavefront Analysis
(Construction according to Huygens Principle)
Observe:
1 2
) 1 2 (l
1(air) = l sin 1 = c1/f 2(glass) = l sin 2 = c2/f
Equate two above relations to get:
Or, Snells Law:
cvacuum c sin 1 vacuum sin 2 c1 c
Lecture-24
Physical Optics Wave-like effects Demonstration Interference Two Huygens wavelets overlap and add to create spatial modulation of intensity. Interference
Question: How does it work?
Note: Light detectors including eyes respond to intensity.
1
Early Quantum Theory Werner Heisenberg (1901-1976)
Max Planck (1858-1947)
Erwin Schrdinger (1887-1961)
Blackbody Radiation and Incandescence
Plancks Quantum Hypothesis
Emin
hf
Where the Planck constant h has a value:
h 6.63 10
34
Js
4.14 10
15
eV s
E
nhf
Lecture-25
Double-Slit Interference Intensity Profile, including Diffraction Interference fringes result from two diffracted intensities from two identical slits. Note L > d. Diffracted light from each slit of width a is E1
E1 ( or 2 ) Eo sin / 2 /2
a E2
Department of Physics, Lehigh University Physics 21- Introductory Physics II Spring 2008 Final Exam May 1, 2008 Closed Note 4:00 PM-7:00 PM Student's Name _Recitation Section Number _ Recitation Leader's Name _
The test is a multiple-choice examination. F
Lecture-26
Blackbody Radiation Wien's Displacement law relates wavelength at maximal emission to temperature as:
P T = 2.90 10-3 mK
Max Planck asserts: i) Emission spectrum from heated surface is same as that from cavity at same temperature; solid
Reading Assignment for Lecture-27
Hydrogen Atom Emission spectrum Bohr's model of hydrogen atom Bohr's energies for orbiting electron de Broglie's hypothesis Bohr's correspondence principle
1
Lecture-26 Examples Example Problem-1 HW26-3. (HRW 35-21) In Fig. 35-39, sources A and B emit long-range radio waves of wavelength 400 m, with the phase of the emission from A ahead of that from source B by 90. The distance rA from A to detector D is
Lehigh University HW-26 Solutions
Physics 21, Spring 2008
April 7, 2008
26-1. (HRW 35-1) The speed of yellow light (from a sodium lamp) in a certain liquid is measured to be . What is the index of refraction of this liquid for the light?
Solution
Lehigh University Physics 21, Spring 2008
April 8, 2008 Home Work Assignment (27-28)
Note: Solutions to the problems must be submitted on WileyPLUS (www.wileyplus.com). HW-27 due April 22 27-1. (HRW 38-7) An ultraviolet lamp emits light of waveleng
Lehigh University
Physics 21 Spring 2008 Equation Sheet
April 12, 2008
1 1 1 = (n - 1) + R R f 2 1
n1 sin 1 = n2 sin 2 S P= c
1 1 1 + = p q f
h2 2 En = 8mL2 n , for n = 1,2,3, K
En = -
me 4 1 , for n = 1,2,3, K 8 o h 2 n 2
Lehigh University HW-25 Solutions
Physics 21, Spring 2008
April 7, 2008
25-1. (HRW 34-107) A fruit fly of height H sits in front of lens 1 on the central axis from the fly; through the lens. The lens forms an image of the fly at a distance the ima
Lehigh University Physics 21, Spring 2008
April 7, 2008 Home Work Assignment (25-26)
Note: Solutions to the problems must be submitted on WileyPLUS (www.wileyplus.com). HW-25 due April 15 25-1. (HRW 34-107) A fruit fly of height H sits in front of
Reading Assignment for Lecture-25
Double-slit interference: Sequence of diffraction and interference Diffraction due to: Square slit; Rectangular slit; Circular aperture; Rayleigh criterion Diffraction grating Polarization of electromagnetic wave
Lecture-24 Examples Example Problem-1 HW-24-4. (HRW 34-98) In Fig. 34-50, an object is placed in front of a converging lens at a distance equal to twice the focal length f1 of the lens. On the other side of the lens is a concave mirror of focal lengt
Lecture-24 Physical Optics Wave-like effects
Demonstration Interference Two Huygens wavelets overlap and add to create spatial modulation of intensity. Interference
Question: How does it work?
Note: Light detectors including eyes respond to inten
Lehigh University HW-24 Solutions
Physics 21, Spring 2008
April 2, 2008
24-1. (HRW 34-43) You produce an image of the Sun on a screen, using a thin lens whose focal length is 20.0 cm. What is the diameter of the image? (See Appendix C for needed d
Lecture-23 Geometrical Optics - continued
Lensmaker's equation
Snell's law gives
and
1 n 2 4 n 3
Parallel lines
R2
h1 1 sin 1 = ; R1 h h2 ; and 2 R2 f Also from figure, we
R1
have
= 1 - 2
= 3 - =
Or,
4
n
- ( 1- 2) =
n
+
n
Lecture-23 Examples Solutions HW-23-5. (HRW 34-33) In Fig. 34-38, a beam of parallel light rays from a laser is incident on a solid transparent sphere of index of refraction n. (a) If a point image is produced at the back of the sphere, what is the i
Lehigh University HW-23 Solutions
Physics 21, Spring 2008
April 2, 2008
23-1. (HRW 33-67) In Fig. 33-65, light enters a 90 triangular prism at point P with incident angle , and then some of it refracts at point Q with an angle of refraction of 90.
Lehigh University HW-21 Solutions
Physics 21, Spring 2008
March 26, 2008
21-1. (HRW 33-1) From Fig. 33-2, approximate the (a) smaller and (b) larger wavelength at which the eye of a standard observer has half the eye's maximum sensitivity. What ar
Reading Assignment for Lecture-23
Polarization of Electromagnetic Waves Geometrical Optics Lenses Lensmaker's equation Thin lens equation Focusing Imaging by ray tracing Magnification Imaging examples: Telescope, microscope, human eye Total intern
Lehigh University HW-22 Solutions
Physics 21, Spring 2008
March 26, 2008
22-1. (HRW 33-24) A small laser emits light at power 5.00 mW and wavelength 633 nm. The laser beam is focused (narrowed) until its diameter matches the 1266 nm diameter of a
Lecture-22
Wavefront is instantaneous surface of uniform phase. For wave propagating in one direction, the wavefront is planar. In three-D space, the wavefront is spherical in shape. Wavefront is perpendicular to direction of wave propagation.
Plana