Physics equations

Question 1

What is Coloumb’s law?

Answer 1

Fe = electrical force

ke = Coloumb constant

Q1 and Q2 = charges

r = separation distance

Question 2

What is Ohm’s law?

Answer 2

V = IR

V = voltage

I = current

R = resistance

Question 3

What is the equation for capacitance?

Answer 3

C = Q/V

C = capacitance

V = voltage

Q = charge

Question 4

What is the law of reflection?

Answer 4

Or = angle of reflection

Oi = angle of incidence

Question 5

What is the refractive index?

Answer 5

n1 = incident index

n2 = refracted index

O1 = incident angle

O2 = refracted angle

Question 6

What is the law of refraction?

Answer 6

(top should be sin1 and v1, bottom should be sin2 and v2)

Question 7

What is the mirror equation and law of thin lenses?

Answer 7

f = focal length

p = object distance

q = image distance

Question 8

What are the equations for tensile stress and shear stress?

Answer 8

A = area

F = force

Question 9

What is the equation for current?

Answer 9

I = dm/dt

I = dV/dt

Question 10

What is the equation for current density?

Answer 10

J = dI/dA

Question 11

What is the equation of continuity?

Answer 11

A1 = cross-sectional area of region 1

v1 = flow velocity in region 1

A2 = cross-sectional area of region 2

v2 = flow velocity in region 2

Question 12

What is Bernoulli’s law?

Answer 12

p = pressure at elevation 1

p (of second and third components) = fluid density

g = acceleration due to gravity

h = height of elevation 1

v = velocity at elevation 1

Question 13

What is Newton’s law of friction?

Answer 13

r = shear stress

n = viscosity

dv = speed difference between layers

dy = thickness of layers

Question 14

What is Reynold’s number?

Answer 14

Re = Reynold’s number

p = density of fluid

u = flow speed

L = characteristic length (eg. radius of tube)

mu = viscosity of fluid

Question 15

What is the equation for the speed of sound?

Answer 15

v (or c) = speed of sound

B = coefficient of stiffness

p = density

Question 16

What is the equation for Doppler shift?

Answer 16

fo = observer frequency of sound

v = speed of sound waves

vo = observer velocity

vs = source velocity

fs = actual frequency of sound waves

Question 17

What is Boyle’s law?

Answer 17

pV = k

k = a constant

p = pressure

V = volume

Question 18

What is the ideal gas law?

Answer 18

pV = nRT

p = pressure

V = volume

n = amount of substance

R = ideal gas constant

T = temperature

Question 19

What is van der Waals equation?

Answer 19

P = pressure

R = universal gas constant

T = absolute temperature

V = molar volume

b = gas constant b

a = gas constant a

Question 20

What is Henry’s law?

Answer 20

c = ap

c = concentration of a dissolved gas

a = Henry’s law constant

p = partial pressure of the gas

Question 21

What is the 1D diffusion equation?

Answer 21

Question 22

What is Bragg’s law?

Answer 22

d = spacing between planes in the atomic lattice

O = angle between incident wave and scattering planes

n = integer determined by order

lambda = wavelength of incident wave

Question 23

What is Stokes shift equation?

Answer 23

absorption and emission both in wave number units

Question 24

What is the equation for resonant frequency of LC circuits?

Answer 24

L = inductance in henries

C = capacitance in farads

Question 25

What is the Larmour frequency in MRI?

Answer 25

w = precession frequency

y = gyromagnetic ratio

B = strength of the externally applied field