General Flashcards
sin 0 sin 30 sin 45 sin 60 sin 90
sin 0 = 0
sin 30 = 0.5
sin 45 = 0.707
sin 60 = 0.866
sin 90 = 1
cos 0 cos 30 cos 45 cos 60 cos 90
cos 0 = 1
cos 30 = 0.866
cos 45 = 0.707
cos 60 = 0.5
cos 90 = 0
tan 0 tan 30 tan 45 tan 60 tan 90
tan 0 = 0
tan 30 = 0.577
tan 45 = 1
tan 60 = 1.73
tan 90 = undefined
centripetal acceleration formulas
ac = v² / r
ac = w²r
ac = 2πv/T
Centripetal force formulae
Fc = mv² / r
Fc = mw²r
Fc = 2πmv / T
tan ø =
tan ø = v² / rg
Mean position properties
x = 0
a = 0
Fres = 0
KE = max
V = max
Extreme position properties
x = max
a = max
Fres = max
KE = 0
V = 0
(SHM)
T =
T = 2π/w
Mass attached to spring
T = 2π √(m/k)
or
T = 2π √(l/g)
s = ?
s = rø
Angular displacement in radian formula
2πt/T
1º =
1 radian
Angular speed formula
2π/T
Angular speed (v)
v = r 2π/T
Which waves needs medium
Mechanical
Longitudinal waves speed (V) depends on
V = √(E/p)
E = elasticity
p = density
Normal medium to denser medium
Mechanical waves EM
frequency constant constant
wavelength inc dec
speed inc dec
Intensity formula
I = E / tA (E/t = power) so
I = Power x Amplitude so
I = 2π² (density) A² f² V
Audible frequency range
20 Hz - 20 kHz
Speed of sound fastest in
Solids then liquids then gases
Factors affecting speed of sound
Inversely proportional to density
The more moist/humid the faster
The higher the temp the faster
Speed of sound in higher temps formula
V = 332 + 0.61t (t = temp of air in Cº)
Constructive and destructive interference path differences
constructive: d = m(wavelength)
destructive: d = m + ½ (wavelength)
Phase differences
Constructive: 2mπ
Destructive: (2m+1)π
Phase difference in terms of path difference (d)
Phase difference = 2π/wavelength x path difference (2π/wave)d
or Phase difference = 360º/wavelength x path difference (360º/wave)d
Plucks at ½ 1/4 and 1/6 or any
l wavelength frequency
½ 2L v/2L
1/4 L v/L
1/6 2L/3 3v/2L
any 2L/n nv/2L
Energy at node vs anti node
Node = 0
Anti node = max
Wavelengths of closed pipe
4L/(2n-1) (only odd)
Wavelengths in open tube
2L/n (all harmonics)
f open =
2f closed
Doppler
Source away = + (Away Add)
Source towards = — (Towards subTracT)
Observer away = — and above
Observer towards = + and above
Doppler what year
1842
First law of thermodynamics
∆Q = ∆U + ∆W
∆U =
Change in internal energy = Change in heat energy flowing in — Flowing out work (On system)
∆U = ∆Q - ∆W
Isochoric
Volume constant so
Q = ∆U
Isobaric
Constant pressure so
∆Q = ∆U + P(V2-V1)
Isothermal
Temp is constant
Q = W
Specific heat of a gas in isothermal process is infinite
Adiabatic
No heat is gained or removed (Q=0)
W = -∆U
Stefan Boltzmann Law
E = ∂T^4
∂ = Stefan Boltzmann constant = 5.67 x 10^-8
Wein’s Law
Wavelength(max) = 1/T
What did Wein’s Law fail to do What is the opposite of Wein’s Law
Wein’s law predicted shorter wavelengths but failed to predict at higher wavelengths
Raleigh Jean’s law predicted only long wavelengths but failed to predict at shorter wavelengths
KE max =
KEmax = hfo — ø
KEmax = threshold frequency — work function
KEmax = min frequency needed to eject e — min energy needed to eject e
KEmax also equals
KEmax = eVo (stopping potential)
In photoelectric effect the stopping potential depends on
Frequency
Electron will have max KE when it has
Short wavelength
Comptons wavelength
0.024 A°
Pair production happens when
Energy greater than 1.02 MeV
Pair annihation
0.51 MeV ???
Emax (coming from infinity)
Wavelength minimum
Emin (coming from one level up)
Wavelength max
isobar
Top same
Bottom different
Isotone
Neutron number same
Mirror nuclei
Proton X = Neutron Y
and vice versa
Radiation examples
Alpha= Radon 222
Beta= Stronium 94
Gamma= Cobalt 60
Continuous vs discrete
Discrete = alpha and gamma
Continuous = beta
Penetration of radiation
Alpha cant get past paper
Beta cant get past Aluminum sheet
Gamma cant get past Lead sheet
Activity units
Rutherford
Baquerel (Bq)
Curie
1 Curie = ____ Bq
1 Rutherford = ____ Bq
1 Curie = 3.7 x 10^10 Bq
1 Rutherford = 10^6 Bq
Activity (A) =
Rate of decay
Decay constant
0.693
Rectification
AC to DC
Forward bias in rectification
High to low potential
Magnetic Force
F = ILBsinø
Tesla
B = F/IL
1 Tesla = Nm-1 A-1
1 Tesla = 1 Wb m-2
1 Tesla = 10^4 Gauss
Flux =
Flux = B • A cos ø
Maximum flux angle
90°
Flux units
Weber
1 Weber = kgm² A-1 s-2
Fb =
Fb = qvB sinø
Faradays Law of EM induction
€ = (NEG) number of loops x flux / time
Step up transformers
inc voltage and inc loops in secondary coil
1 kWh =
3.6 MJ
Conductance (G)
1/R
Conductance units
mho and Siemen
Conductivity unit
mho/m
Siemen/m
smaller power lamp glows ____
brighter