Laws in Physics Flashcards
What is Faraday’s Law?
Magnetic Fields
Faraday’s Law: the magnitude of induced e.m.f. is equal to the rate of change of flux linkage.
ε = N (ΔΦ/Δt)
What is Lenz’s Law?
Magnetic Fields
Lenz’s Law: an induced current is always in a direction so as to oppose the change that caused it.
What is Kepler’s Third Law?
Gravitational Fields
Kepler’s Third Law: the square of an object’s orbital period (T) is directly proportional to the cube of its orbital radius (r).
T^(2) ∝ r^(3)
(Time 2 Read 3)
What is Coulomb’s Law?
Electric Fields
Coulomb’s Law: The size of the force that acts between two point charges is proportional to the product of their charges and inversely proportional to the square of their separation.
F = 1/(4𝜋𝜀0) x (𝑄1𝑄2)/(𝑟^2)
1/(4𝜋𝜀0) is a constant, so
F ∝ (𝑄1𝑄2)/(𝑟^2)
It is attractive for opposite charges and repulsive for like charges
What is Snell’s Law?
Waves
Snell’s Law: n1sinθ1 = n2sinθ2
Where:
n1 = refractive index of the first material
n2 = refractive index of the second material
θ1 = angle of incidence (angle incoming ray makes to the normal)
θ2 = angle of refraction (angle refracted ray makes to the normal)
What is Newton’s 1st Law?
Mechanics
Newton’s 1st Law: the velocity of an object will not change unless a resultant force acts on it.
(1st because velocity, 1st gear)
What is Newton’s 2nd Law?
Mechanics
Newton’s 2nd Law: acceleration is proportional to force.
F = m x a
(2nd because m and a, 2)
What is Newton’s 3rd Law?
Mechanics
Newton’s 3rd Law: each force has an equal and opposite reaction force.
What is Hooke’s Law?
Materials
Hooke’s Law: extension is proportional to force.
F = kΔL
F ∝ ΔL
Hooke’s Law stops working when the force is great enough.
What is Boyle’s Law?
Thermal Physics
Boyle’s Law: at a constant temperature, the pressure and volume of a gas are inversely proportional.
pV = constant
(Boys Piss and Vomit)
What is Charles’ Law?
Thermal Physics
Charles’ Law: at a constant pressure, the volume of a gas is directly proportional to its absolute temperature.
V/T = constant
(Charles Vacates over in Tennessee)
What is the Pressure Law?
Thermal Physics
Pressure Law: at constant volume, the pressure of a gas is directly proportional to its absolute temperature.
p/T = constant
(Poo Poo Time)
What is Kirchoff’s First Law?
Electricity
Kirchoff’s First Law: total current entering a junction = total current leaving it.
What is Ohm’s Law?
Electricity
Ohm’s Law: for an ohmic conductor, current is directly proportional to the potential difference across it, given that physical conditions (e.g temperature) are kept constant.
What is Kirchoff’s Second Law?
Electricity
Kirchoff’s Second Law: the total e.m.f. around a circuit = the sum of the p.d.s across each component.
ε = ΣIR
What is the First Law of Thermodynamics?
Thermal Physics
First Law of Thermodynamics:
Increase in internal energy = Energy supplied by heating + Work done on the system
When a substance changes state, its internal energy changes (J) but its kinetic energy and temperature stays the same.
This is because the potential energy of the particles is altered - not their kinetic energy.
