Review
1. What have we studied?
1.1. Electrics, Magnetics and Electromagnetism 1.
2. Optics
2. Important knowledge
2.1. Electromagnetism
2.1.1. Fields
2.1.1.1. Electric field: 0
q F
E
=
2.1.1.2. Magnetic field:
B
→
2.1.2. Forces
2.1.2.1. Electrostatic force: r r
q q F E ?412
210 πε=, Permittivity constant: 2
12120m N C 1085.8---???=ε
2.1.2.2. Magnetic force: B v q F B
?=
Permeability constant:
m/A T 10 26.1m/A T 104 670??≈??=--πμ
2.1.
3. Potential energy: app i f W W U U U =-=-=?
2.1.
3.1. C q U E 22
= :time any at capacitor the of field electric the in stored energy The
2.1.
3.2. 2
2
Li U B =:time any at ind uctor the of field magnetic the in stored energy The
2.1.4. Electric potential: q
U V =
2.1.5. ??-=-=-=?f i
i f s d E q W
V V V 0
:difference potential E lectric 2.1.6. Laws
2.1.6.1. Coulomb’s Law: r r
q q F E ?412
210 πε= 2.1.6.2. flux electric the creates :y electricit for law Gauss ,0
enc enc
q q A d E →=
??ε
2.1.6.
3. 0
=??A d B
:magnetism for law Gauss know) we as far (as exist not do monopoles Magnetic →
2.1.6.4. dt
d s d E B
Φ-=?? :
law s Faraday'field electric induced create will flux magnetic Changing →
2.1.6.5. enc E
i dt
d s d B 00
0 μεμ+Φ=?? :induction of law s Maxwell'- Ampere field magnetic induced create will current enclosed and flux electric Changing
→
2.1.7. Concepts in electric circuits
2.1.7.1. Current: dt
dq
i =
2.1.7.2. dA
di J =
:density Current
2.1.7.
3. Resistance: i V R =
2.1.7.4. Capacitance: V
q C = 2.1.7.5. Inductance: i
N L B
Φ=
2.1.8. Electromagnetic Oscillations And Alternating Current
2.1.8.1. Angular frequency of LC Oscillations: LC
1
=
ω 2.1.9. RC Circuit
2.1.9.1. RC =τ :constant time Capacitive
2.1.10. dq
dW
=
ε :emf 2.1.11. Multiloop Circuit
2.1.11.1. L oop rule: based on the conservation of energy 2.1.11.2. J unction rule: based on the conservation of charge
2.2. Optics
2.2.1. Images
2.2.1.1. Two Types of Images: real and virture 2.2.1.2. Mirrors
2.2.1.2.1. Plane Mirrors:
2.2.1.2.1.1. p i -=:position Image 2.2.1.2.1.2. i r θθ=:reflection of Law 2.2.1.2.2. Spherical Mirrors
2.2.1.2.2.1. ??
?<<>>==
)0( 0)
0 ( 02r r r f mirror spherical convex
for mirror spherical concave for :length Focal 2.2.1.2.2.2. f
i p 1
11=+:
position Image 2.2.1.2.2.3. ??
?<>=>image
virtual for image real for object real For 0
0),
0( i p 2.2.1.3. Spherical Refracting Surface
2.2.1.
3.1. r
n n i n p n 1
221-=+:
position Image 2.2.1.3.2. ??
?<>=>image
virtual for image real for image object real For 0
0:)0( i p
2.2.1.
3.3. ??
?<>=surface concave facing object the for surface convex
facing object the for :radius Curvature 00 r 2.2.1.4. Thin Lens
2.2.1.4.1. f
i p 111=+:
position Image 2.2.1.4.2. ()???
? ??--=211111
r r n f :equation) s maker' (lens length
Focal 2.2.1.4.3. ?
?
?<>=>image virtual for
image real for image object real For 00 :)0( i p
2.2.1.4.4. ??
?<>=e
00 surfac concave facing object the for surface convex
facing object the for :radius Curvature r
2.2.1.4.5. ?
??<>=lens diverging for lens converging
for :length Focal 00 f
2.2.1.5. Locating Images of Extended Objects by Drawing Rays 2.2.1.6. Two - Lens System: 12i L p -=
2.2.2. Interference
2.2.2.1. Huygens’ principle
2.2.2.2. 2211sin sin θθn n =:refraction of Law 2.2.2.
3. Wavelength λand Index of Refraction v
c
n = 2.2.2.4. Phase Difference L k L
?=?=?πλ
φ2
2.2.2.5. Double -slit interference
θsin d L =?:difference length Path
θλπφφsin 2,21cos 420d L k I I =?=???
??=:Intensity
,2,1,0 ,sin max ±±===?m m d L λθ:p osition M axima
??
? ??=→-d m λθ1max sin
,2,1,0 ,21sin min ±±=??? ?
?
+==?m m d L λθ:position M inima
???
?????? ?
?+=→-d m λθ21sin 1min
2.2.2.6. Interference From Thin Films
L ΔL 2 =difference length Path
2.2.
3. Diffraction
2.2.
3.1. Diffraction By A Single Slit
()2
0sin ??
?
??=ααθI I :Intensity , θλπαsin a =
2.2.
3.2. Diffraction By a Double Slit
Intensity: ()()
2
20sin cos ??
?
??=ααβθI I , θλπβθλπαsin ,sin d a =
= 2.2.3.3. Diffraction Gratings:
,2,1,0,sin ==m m d λθ:axima)equation(m Grating
θ
λ
θcos Nd hw =?:lines the of width Half
θ
λθcos d m
D =
??=
:Dispersion Nm R avg
=?=
λ
λ:pow er Resolv ing 2.2.3.4. Diffraction By A Circular Aperture
d
λ
θ22
.1sin =:minimum First
Rayleigh’s criterion for resolvability: ??
?
?
?==-d A R λθθ22
.1sin 1
第4章 功和能Work and Energy
第4章功和能 质点受力的作用时，如果持续一段时间，质点的动量会 改变；如果质点由空间位置的变化，则力对位移的累积（功）会使质点的能量（动能和势能）发生变化。对功和能的研究，是经典力学中重要的组成部分。 与机械运动相联系的能量守恒定律（机械能守恒定律），是普遍的能量守恒定律的一种特殊形式。
本章主要内容 §4.1功 §4.2动能定理 §4.3保守力与势能 §4.4引力势能和弹性势能§4.5由势能求保守力 §4.6 机械能守恒定律 §4.7 守恒定律的意义 §4.8碰撞
§4.1 功 Work
功——力在位移方向上的分量与位移大小的乘积。 1.功的定义 θ cos d d d r F r F A t ?==设质点受力为，它的空间位置发生一无限小的位移—— 位移元，则该力做功表示为 r d F A d r F A d d ?=θ F r d A B L 注意：功是一个标量。有正有负： 当时，；?<≤900 θ0A >d 当时，。?≤
结论：合力的功等于各分力沿同一路径所做功的代数和。 ∑∑??∑?=?=??? ? ??=?=i i i B A i B A i i B A A r F r F r F A d d d 如果质点同时受到多个力的作用，计算它们等效合力的功： t A t A P t d d lim 0= ??=→?功率的定义：单位时间内所做的功。即 2.合力的功 3.功率
Review 1. What have we studied? 1.1. Electrics, Magnetics and Electromagnetism 1. 2. Optics 2. Important knowledge 2.1. Electromagnetism 2.1.1. Fields 2.1.1.1. Electric field: 0 q F E = 2.1.1.2. Magnetic field: B → 2.1.2. Forces 2.1.2.1. Electrostatic force: r r q q F E ?412 210 πε=, Permittivity constant: 2 12120m N C 1085.8---???=ε 2.1.2.2. Magnetic force: B v q F B ?= Permeability constant: m/A T 10 26.1m/A T 104 670??≈??=--πμ 2.1. 3. Potential energy: app i f W W U U U =-=-=?
2.1. 3.1. C q U E 22 = :time any at capacitor the of field electric the in stored energy The 2.1. 3.2. 2 2 Li U B =:time any at ind uctor the of field magnetic the in stored energy The 2.1.4. Electric potential: q U V = 2.1.5. ??-=-=-=?f i i f s d E q W V V V 0 :difference potential E lectric 2.1.6. Laws 2.1.6.1. Coulomb’s Law: r r q q F E ?412 210 πε= 2.1.6.2. flux electric the creates :y electricit for law Gauss ,0 enc enc q q A d E →= ??ε 2.1.6. 3. 0 =??A d B :magnetism for law Gauss know) we as far (as exist not do monopoles Magnetic → 2.1.6.4. dt d s d E B Φ-=?? : law s Faraday'field electric induced create will flux magnetic Changing → 2.1.6.5. enc E i dt d s d B 00 0 μεμ+Φ=?? :induction of law s Maxwell'- Ampere field magnetic induced create will current enclosed and flux electric Changing → 2.1.7. Concepts in electric circuits 2.1.7.1. Current: dt dq i = 2.1.7.2. dA di J = :density Current