Wave

9.1

reflection:

phase: offset of the wave from a reference point

Name	Symbol	Unit
wavelength	\lambda	m
frequency	f	hz
period	T	s
wave speed	v	m/s

Equation	Explain
v=f\lambda
f=\frac{1}{T}

9.2

refraction: a: normal, b: at critical angle, c: total internal reflection

Name	Symbol	Unit
index of refraction	n	none
speed of light	c	m/s
critical angle	\theta_{c}	^{\circ}

Equation	Explain
n=\frac{c}{v}	v: speed of light in that material
n_{1}sin\theta_{1}=n_{2}sin\theta_{2}
\frac{n_{2}}{n_{1}}=\frac{\lambda_{1}}{\lambda_{2}}
sin\theta_{c}=\frac{n_{2}}{n_{1}}	n_{1}: from material n_{2}: to material

9.3

diffraction:

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interference:

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if \lambda \geq w: noticeable diffraction, else: very little

Name	Symbol	Unit
distance between two slits	d	m
node (destructive) number	n	-
antinode (constructive) number	m	-
distance from the center of the slit to the point / distance from the slit to the screen	L	m
distance from the center of the screen to the point	x	m
path length difference (difference of the distance from a point to two sources)	\Delta s_{n}	m

Equation	Explain
dsin\theta_{n}=(n-\frac{1}{2})\lambda	\theta_{n}: angle for the nth nodal line
d\frac{x_{n}}{L}=(n-\frac{1}{2})\lambda
$\Delta s_{n}=	PS_{1}-PS_{2}
\Delta s_{n}=(n-\frac{1}{2})\lambd

9.5 Double Slit

Name	Symbol	Unit
distance between light / dark spots on the screen	\Delta x	m

Equation	Explain
dsin\theta=m\lambda
dsin\theta=(n-\frac{1}{2})\lambda
x_{m}=m\frac{L\lambda}{d}
x_{n}=(n-\frac{1}{2})\frac{L\lambda}{d}
\Delta x=\frac{L\lambda}{d}

10.1 Thin Film

Light travelling in low n, reflected by high n -> phase change by 180^{\circ}
Light travelling in high n, reflected by low n -> phase doesn't change

Air Wedge:

Name	Symbol	Unit
Height of the thin film/air wedge	t	m
The number of extra wavelengths the wave travels in the film	N	-

Equation	Explain
\lambda_{film}f_{film}=\frac{c}{n_{film}}
\lambda_{film}=\frac{\lambda_{vac}}{n_{film}}
N=\frac{2t}{\lambda_{film}}
x_{1}=\frac{L\lambda}{2t}	Equation for an air wedge x_{1}: first destructive interference, also the seperation between the fringes

10.2 Single Slit

Name	Symbol	Unit
width of the slit	w	m
distance from the center of the screen to the point	y	m

Equation	Explain
\Delta L=\frac{w}{2}sin{\theta_{n}}
wsin\theta_{n}=n\lambda
wsin\theta_{m}=(m+\frac{1}{2})\lambda
\Delta y=\frac{L\lambda}{w}
\Delta y=\frac{y_{n}}{n}

10.4

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Last update: May 27, 2021
Created: May 5, 2021