Gravity and Motion
What is the force that keeps an object moving in a curved, circular path of motion?
Centripetal force
What law describes the electrostatic force between two objects?
Coulomb’s law
What is the difference between an inertial and non-inertial reference frame?
An inertial reference frame does not accelerate (Newton’s laws are upheld). A non-inertial is accelerating or rotating.
Describe two things about a photon
- Discrete (quantum) packet of energy
- Behaves as a particle and a wave (wave-particle duality)
- Makes up light and electromagnetic radiation
- Generally travels at 3x10^8m/s
Name the six types of quarks.
Up, down, top, bottom, charm, strange.
According to Newton’s Law of Universal Gravitation, how does gravitational force change if the distance between two objects doubles?
The gravitational force is reduced to 1/4 of the original value (inverse square relationship)
What is a similarity between an electric field and a magnetic field?
They are both regions around a charged object where a force is experienced.
Explain the concept of simultaneity and why two events that appear simultaneous to one observer may not be simultaneous to another
Because the event and observer are in different reference frames, this is significant when the event is happening close to the speed of light.
What does the work function represent in the photoelectric effect?
The boundary for a metal to eject a photoelectron when hit by a photon.
Any photon with energy above the work function will displace a photoelectron from the metal.
What are the names of the two fundamental matter particles in the Standard Model?
Quarks and Leptons
What is normal force?
Force that acts on an object perpendicular to the surface the object is on.
Describe Faraday’s law of electromagnetic induction
Explains how a change in magnetic flux results in an electromotive force (EMF)
Explain time dilation using the flashlights on a train paradox
The person on the train experiences both lights reaching either end of the carriage at the same time.
The person on the platform sees the flashlight beamed in the same direction as the train is travelling reach the carriage end first because the train and beam of light are moving toward each other.
GOLDEN RULE OF RELATIVITY: “Moving clocks run slow” - Albert Einstein
Explain Young’s Double Slit Experiment and what it says about light’s behaviour.
Light is shone through slits in a material. The beams interfere forming wave patterns by creating alternating white and dark bands on a screen.
It proves that light behaves as a wave.
Which gauge boson mediates the electromagnetic force between electrically-charged particles?
Photons
Describe Kepler’s second law
A radius vector joining any planet to the sun sweeps out equal areas in equal lengths of time.
What is the name of the left-hand rule and what does each finger represent?
Fleming’s left hand rule
Thumb - Force (F)
First finger - Magnetic field direction (B)
Second Finger - Current (I)
Explain length contraction using the ladder in a barn paradox.
From the barn’s perspective the ladder contracts and fits inside the barn. From the ladder’s perspective, the barn contracts and the ladder does not fit.
Explain the Photoelectric Effect and what it says about light’s behaviour.
Light transfers energy in discrete packets called photons, which either do or do not have enough energy to displace a photoelectron from certain metals.
It proves that light behaves as a particle.
What is the difference between a lepton and a quark?
Leptons mediate electromagnetic force and weak nuclear force.
Quarks mediate strong nuclear force in addition to the others.
Why can an object in circular motion be accelerating yet maintain constant speed?
When the centripetal force pulls the object towards the centre, the object changes direction accelerating towards the centre but it‘s speed does not change.
Explain why Lenz’s law is important to upholding the law of conservation of energy
An induced current always opposes the change in flux that caused it to avoid creating an infinite cycle of more flux, higher current, more flux, higher current until all the energy in the Universe is used up.
Explain why muons are able to reach Earth when their half-life indicates they should decay before reaching Earth’s surface.
Length contraction - From the muon’s perspective, the length travelled to the Earth’s surface is contracted
Time dilation - From the observer’s perspective, the muon experiences dilated time and is therefore able to reach Earth before decaying
What is black-body radiation and why is it important?
A theoretical object that absorbs all wavelengths of light and reflects none.
Classical physics predicts that increasing input wave frequency should increase output energy forever.
Real experiments show that ultraviolet lights max out the output light intensity.
Why must symmetry always exist in particle interactions?
To obey the laws of conservation of mass and momentum.