Module 5 Flashcards
Internal Energy
The total sum of randomly distributed kinetic energy and potential energy of particles in a substance.
Thermal Equilibrium
No net transfer of thermal energy between bodies in thermal contact (they are at the same temperature).
Specific Heat Capacity
The energy required to raise the temperature of a unit mass of a substance by one kelvin.
Specific Latent of Fusion
The energy required per unit mass to change a substance from solid to liquid at constant temperature (or vice versa).
Specific Latent Heat of Vaporisation
The energy required per unit mass to change a substance from liquid to a gas at constant temperature (or vice versa).
Boyle’s Law
Pressure is inversely proportional to volume for a fixed mass of ideal gas at constant temperature.
Absolute Zero
The temperature at which all substances have their minimum internal energy (-273°C).
Avogadro’s Constant
The number of atoms of carbon-12 in 0.012 kg (12g) of carbon-12.
Centripetal Force
A resultant force which acts perpendicular to the direction of motion, instantaneously towards the centre of a circle.
Simple Harmonic Motion
Oscillating motion where the acceleration is directly proportional to the displacement and is always directed towards the equilibrium position.
Isochronous Oscillator
An oscillator that has the same time period regardless of its amplitude. The period of a simple harmonic oscillator is isochronous.
Free Oscillations
The oscillations are not caused by an external periodic driving force. The system oscillates at its natural frequency.
Forced Oscillations
The oscillations are caused by an external periodic driving force. The system oscillates at the driving frequency.
Gravitional Field Strength
Force per unit mass at a point in a gravitational field.
Newton’s Law of Gravitation
The gravitational force of attraction exerted on one object by another object is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centres of mass.
Kepler’s First Law
The orbit of a planet is an ellipse with the Sun at one of the two foci.
Kepler’s Second Law
A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time.
Kepler’s Third Law
The square of the orbital time period of a planet is directly proportional to the cube of the planet’s mean distance from the Sun.
Geonstationary Orbit
The satellite is always vertically above the same point on the surface of the planet.
Gravitational Potential
The work done per unit mass to bring an object from infinity to a point in the gravitational field.
Escape Velocity
The minimum velocity required by an object to have just enough energy to be able to leave a specified gravitational field.
Energy Level
A discrete amount of energy that an electron within an atom is allowed to possess.
Wein’s Displacement Law
The peak wavelength, at which the intensity of radiation emitted from the black body is maximum, is inversely proportional to the absolute temperature of its surface.
Stefan’s Law
The luminosity (radiant power) of a black body is directly proportional to its surface area, and to the absolute temperature of its surface to the fourth power.
Astronomical Unit
The mean distance from the Earth to the Sun (1.5x10^11m).
Parsec
The distance at which a radius of 1 AU that subtends an angle of 1 arc second (3.1x10^16m).
Cosmological Principle
The universe is homogeneous and isotropic on large scales, and the laws of physics are universal.
Homogenous
Matter is uniformly distributed everywhere in the universe.
Isotropic
The same in all directions. There is no centre to the universe.
Hubble’s Law
The recessional speed of a galaxy is directly proportional to its distance from the Earth.
Doppler Effect
The observed change in the frequency/wavelength of waves due to the source of the waves moving relative to the observer.
