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CH21 AC circuits and EM waves
[
21
.1] AC generator:
∆v=∆V
max
sin 2πft
[
21
.2] I
rms
= I
max
/ sprt
(2)
Also important:
P = I
rms
^2 R
[
21
.3] V
rms
= V
max
/ sprt
(2)
Resistance
[
21
.4a]
∆V
(R,rms)
= I
rms
* R
[
21
.4b]
∆V
(R,max
) = I
max
* R
Capacitors:
[
21
.5]X
C
= 1 / (2 π f C)
[
21
.6] ∆V
(C,rms)
= I
rms
* X
C
Inductors
[
21
.8] X
L
= 2 π f L
[
21
.9] ∆V
(L,rms)
= I
rms
* X
L
RLC Series Circuit
i=I
max
sin 2πft
impedance Z of circuit:
[21.x]
Z = sqrt
([R
2
+ (X
L
– X
C
)
2
])
[
21.x]
∆V
max
= I
max
* Z
∆V
rms
= I
rms
* Z
[21.x]
tan = (X
ϕ
L
– X
C
) / R
Power in AC Circuit
[21.x]
P
av
= I
2
rms
R
[21.x]
P
av
= I
rms
∆V
rms
cos
, cos
is power factor
ϕ
ϕ
Resonance in a series RLC Circuit
[21.x]
f
0
= 1 / (2π sqrt
(LC))
CH22 Reflection and Refraction
Refraction:
Index of refraction , n:
N = speed of light in vac / speed of light in medium = c/v
Frequency does not change, speed and wavelengths change.
[22.x]
SNELLS LAW
n
1
sin
ϴ
1
= n
2
sin
ϴ
2
Total internal reflection
ϴ
c
= critical angle where
ϴ
2
= 90
Light goes from high n to low n, ie glass to air
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This note was uploaded on 11/03/2008 for the course PHYS 142 taught by Professor Coleman during the Spring '08 term at Emory.
 Spring '08
 Coleman
 Physics, Resistance

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