Equations Flashcards
Wave speed
c = fλ
c is speed
f is frequency
λ is wavelength
Period
…and what is period?
T = 1/f
T is period
f is frequency
…The period, T, is the time required for one complete cycle and the unit is seconds.
Intensity
…and what is intensity?
I = P/4πr2
P- power of the source
r- distance from a point source
… intensity is the power transferred per unit area
Stretched string frequency
f = 1/2l √T/μ
l is the length of the vibrating string
T is the tension in the string
μ is the mass per unit length of the string material
Beat frequency
f = f1 - f2
The beat frequency is equal to the difference between the frequencies of the individual strings.
Fringe spacing
w= λD/s
λ is the wavelength of the light
s is the separation of the slits
D is the distance from the double slit to the screen
Diffraction grating
nλ = d sin θ
n is the order of the image
λ is the wavelength
d the grating spacing
θ the angle the image makes with a line normal to the grating
Half beam width
sin θ = λ/a
a is dish aperture diameter
Snell’s law
n1 sin()1 = n2 sin()2 n1 and n2 are the absolute refractive indices of the transparent substances 1 and 2.
Absolute refractive index of a substance
ns = c/cs
c is speed of em waves in a vacuum
cs speed of em waves in the substance
Critical angle for two substances
Sin0c = n2/n1
Refractive index
ns = 1/sin0c
Photon energy
E = hf
E- photon energy
h- Planck constant
f- frequency
Einstein’s photoelectric effect equation
hf = φ + Ek
h- plancks constant
f- frequency
φ- work function
Ek- maximum kinetic energy of the photoelectron
De Broglie wavelength
λ = h/mv
h- plancks constant
mv- momentum of the particle
