Special Relativity
What are the two fundamental postulates of special relativity
1) the laws of physics are the same for all observers in uniform motion (inertial frames)
2) the speed of light in a vacuum is the same for all observers, regardless of the motion of the light source
What is the unit of magnetic field.
Tesla
What is threshold frequency?
The minimum frequency of light needed to eject electrons from a metal.
Name the three families of fundamental particles.
Quarks, leptons, bosons
State Newton’s Law of Universal Gravitation
Every mass attracts every other mass proportional to the product of their masses and inversely proportional to the square of the distance between them
A spaceship moves at 0.6c0.6c0.6c. If 10 seconds pass on Earth, how much time passes on the spaceship?
8 seconds
What is Lenz's Law?
The law sates that the induced emf in a circuit opposes the change in magnetic flux
What is wave-particle duality and what is some evidence for it?
Light as a wave is self propagated electric fields and magnetic fields to form an EMR.
Evidence - Young's double slit, reflection, refraction
Light as a particle is quantisized energy in a form of a photon.
Evidence - Photoelectric Effect, Blackbody Radiation
Name the particle that is responsible for the weak nuclear force.
W and Z Boson
What is the formula to calculate the horizontal acceleration down an inclined plane.
a = mg sinθ
Explain why no object with mass can be accelerated to the speed of light.
Because as velocity increases, relativistic mass (or required energy) increases without bound, requiring infinite energy to reach ccc.
What are the different right hand rules and what are they used for?
1. grip rule - direction of magnetic field or current of a wire
2. grip rule - direction of magnetic field or current of a solenoid
3. slap rule - direction of force or magnetic field of a current carrying wire/particle
Write the equation that relates photon energy to frequency
E = hf
How many quarks are needed to make a baryon?
3
Calculate gravitational force between Earth (5.97×10²⁴ kg) and 70 kg astronaut at surface (6.37×10⁶ m).
F = 690N
A spacecraft is 100 m long when at rest. If it travels at 0.8c0.8c0.8c, what length is observed from Earth?
60m
A circular coil of radius 0.10 m with 50 turns is placed in a uniform magnetic field of 0.40 T. The field is perpendicular to the coil. If it is rotated 90° in 0.20 s, what is the average induced emf?
emf = 3.14V
The work function of a metal is 2.5 eV. What is the maximum kinetic energy of electrons emitted when light of wavelength 400 nm shines on the metal in eV?
KE = 0.6eV
Name the four bosons
Photon, Gluon, W+/W-, Z
Satellite orbits 300 km above Earth. Find orbital speed
v = 7.7 × 10³ m/s
Muons at rest have a lifetime of 2.2 μs and they travel at 0.98c. Based on Newtonian Physics Explain, the muon should decay before reaching Earth's surface. How muons are detected on Earth?
The muon is able to reach Earth's surface due to time dilation and length contraction.
The observer on Earth sees the muon exist for a longer time as they see its' time dilate.
From the reference of the muon, the Earth looks like it's moving towards it near the speed of life, the distance between Earth and the muon will contract
A transformer has 200 turns on the primary coil and 50 turns on the secondary coil. The primary voltage is 240 V AC, and the transformer is 90% efficient. If the secondary supplies a current of 4.0 A, what is the power output and the current in the primary coil?
Primary Current = 1.11A
An electron is accelerated through a potential difference of 150 V. Calculate its de Broglie wavelength. (h = 6.63 × 10^-34 J·s, m_e = 9.11 × 10^-31 kg, e = 1.60 × 10^-19 C)
λ ≈ 1.0 × 10^-10 m
In the reaction p+p→p+p+p+pˉ, show that baryon number is conserved.
Yes. Each proton has baryon number +1.
On the left: total = +2. On the right: 3 protons (+3) and 1 antiproton (–1) → total = +2. Baryon number is conserved.
A satellite is in circular orbit 500 km above Earth’s surface. Calculate its orbital speed. (Use Earth’s radius = 6.37 × 10^6 m, mass of Earth = 5.97 × 10^24 kg, G = 6.67 × 10^-11 N·m²/kg²)
v = 7600 m/s