waves + quantum Flashcards
equation for frequency (f)? (T)
f = 1/T
where T = time period
wave equation? (v, f, λ)
v = f x λ
where v = wave speed, f = frequency and λ = wave length
how long is distance from one node to the next antinode?
distance from node to antinode = 0.25λ
equation for wave speed (v) [of vibrations] along stretched string? (T, µ)
v = √(T/µ)
where T = tension of string and µ = mass per unit length (mass of 1 m) of string
equation for nλ (wavelength at particular order line)? (d, x, L)
[FOR YOUNG’s DOUBLE SLIT + DIFFRACTION GRATING]
nλ = (dx)/L
where d = slit spacing, x = fringe spacing, L = distance from source to screen
equation for nλ? (d, θ)
[FOR DIFFRACTION GRATING ONLY] (bc it uses small angle approximation)
nλ = dsinθ
where n = order line numer, λ = wavelength, d = slit spacing and θ = angle of diffraction
equation to find refractive index (n) for wave passing from medium 1 into medium 2? (v1, v2, sin(i), sin(r))
n = v1/v2 = sin(i)/sin(r) (= λ1/λ2)
equation for absolute refractive index (n)? (c,v)
n = c/v
equation for snell’s law? (n1, θ1, n2, θ2)
n1sinθ1 = n2sinθ2
OR
n1sinθi = n2sinθr
equation for critical angle (c) for wave passing from air to medium? (n)
n = 1/sinc
where n = [absolute] refractive index and c = critical angle
equation for energy (E) of a photon? (h, f)
E = hf
where h = planck’s constant and f = frequency of photon
equation for energy (E) of a photon? (h, c, λ)
E = hc/λ
(where c = speed of light)
‘equation’ for intensity?
light as particle:
intensity ∝ no. of photons arriving each second
light as a wave:
intensity ∝ (amplitude^2)
equation for intensity (P, A)
intensity = power/cross-sectional area
I = P/A
(think IPA like the beer at work)
equation for [maximum] kinetic energy (E) of photoelectron? (h, f, Φ)
[FOR PHOTOELECTRIC EFFECT]
E = hf - Φ
or
0.5m(v^2) = hf - Φ
where hf = energy of incident photon and Φ = work function (minimum energy required for photoelectron to be released from surface of metal)
