Equations and constants Flashcards
Specific charge
charge (C) /mass (Kg) unit- C/Kg
The energy of a photon
Planck constant (J) * frequency (Hz) unit- Js (joule seconds)
work function
Planck constant * threshold frequency
photoelectric equation
Planck constant * frequency(hz) = work function(j) + KE(max)(j)
stopping potential of an electron
stopping potential * charge of electron = kinetic energy
the equation for the change in energy between energy levels
ΔE=E1-E2=hf (this shows that the change in energy level is exactly equal to the energy of the photon emitted)
de Broglie’s equation for wavelength
wavelength= plank constant / momentum
Frequency (using #oscillations)
oscillations / time(s)
Frequency (using periods)
1 / period(s)
wave speed
frequency(Hz)*wavelength (m) speed in m/s
string tension
mass held(kg) * gravity(m/s^2) tension-N
mass per unit length of a string
mass of string(kg) / length(m)
mass per length in Kg/m
frequency of the first harmonic of a string
(1/ (2*length(m))) * (square root (tension(N)/ mass per unit length(Kg/m))) frequency in Hz
spacing between fringes in the double-slit experiment
(λ*distance from slits to screen)/space between slits
the pattern of a diffraction grating
slit spacing * Sin(angle between the maximum and zero-order line) = λ of incident light * order of the maximum
slit spacing
1/x (x= number of slits per meter)
refractive index
speed of light in a vacuume / speed of light in the material
Snell’s law
starting refractive indexSin(i)=ending refractive indexSin(r)
the equation for the critical angle
Sin (the critical angle) =
the refractive index of the less optically dense material
/
the refractive index of the more optically dense material
moment of a force
force (N) * perpendicular distance from the turning point to the line of action of the force (m)
moment in Nm
moment of a couple
force (N) * perpendicular distance between the lines of action of the two forces (m)
velocity
Δdisplacement / Δtime
average speed/velocity
total distance (or displacement for velocity) / total time
acceleration
Δvelocity / Δtime
S, U, V, A, T equations
v=u+at
s= ((u+v)/2)t
s= (ut) + 1/2(at^2)
v^2= u^2 + 2as
verticle and horizontal components of a projectiles displacement on a trajectory graph
verticle displacement- Total displacement* Sin(θ)
horizontal displacement- Total displacement* Cos(θ)
vertical and horizontal components of a projectiles velocity on a trajectory graph
vertical velocity- total velocity* Sin(θ)
horizontal velocity- total velocity* Cos(θ)
observed value
true value + Random error + systematic error