Paper 1 Flashcards
What is the formula for specific charge?
(Charge x 1.60x10^-19) / (Mass x 1.67x10^-27)
Define Specific charge of an atom?
The specific charge is defined as its charge divided by its mass.
What is the ground state?
The ground state is the lowest energy level in the atom.
How do you convert eV to joules?
How do you convert joules to eV?
eV to joules
x1.60x10^-19
Joules to eV
How many types of mesons are there and what are they?
There are 7 types of meson, they are K^0 (dS), K^+ (uS)
Pie^- (dU) Pie^0 (uU, dD, sS) Pie^+ (uD)
K^- (sU) K^0 with a line on the top (sD)
What is a superconductor?
A wire or device made of a material that has zero resistivity at and below a critical temperature that depends on the material.
Where are superconductors used?
They are used to make high-power electromagnets that generate very strong magnetic fields in devices such as MRI scanners and particle accelerators.
What are the formulas for working out the distance in projectiles?
For the x direction: Distance = Ut
For the y direction: Distance = 1/2gt^2
Define emf?
The electromotive force of a source is the loss of potential difference per unit current in the source when current passes through the source.
What is annihilation?
Annihilation occurs when a particle and a corresponding antiparticle meet and their mass is converted into radiation energy. Two photons are produced in the process (this ensure a total momentum of zero after the collision, one can’t do this)
What is a lepton and baryon number?
A baryon number is a number of baryons in an in a system of subatomic particles minus the number of antibaryons.
A lepton number is assigned to everyone lepton (+1) and antilepton (-1), on the basis that the total lepton number for each branch of the lepton family is always conserved.
Describe the photoelectric effect
The photoeletric effect, was the emission of electrons from a metal surface when light is directed at the surface.
What is the equation for beta plus and beta minus decay?
For beta plus:
- The atom decays through the W^+ Boson into a B^+ and a neutrino
For beta minus:
- The atom decays through the W^- Boson into a B^- and an antineutrino
Describe the photoelectric effect
The photoeletric effect, was the emission of electrons from a metal surface when alight is directed at the surface and the light has a frequency greater than the minimum value (threshold frequency)
What is Ohm’s law?
Ohm’s law states that the PD across a metallic conductor is proportional to the current through it, provided the physical conditions do not change.
What is a potential divider, and where is it used?
A potential divider consists of two or more resistors in series with each other and with a source of fixed potential difference. The potential difference of the source is divided between the components in the circuit, as they are in series with each other. By making a suitable choice of components, a potential divider can be used:
- the supply a PD which is fixed at any value between zero and the source PD
- to supply a variable PD
- to supply a PD that varies with a physical condition such as temperature or pressure
What is the definition of the principle of moments?
The sum of the clockwise moments equals the sum of the anticlockwise moments when in a closed system.
Define stress and strain, and what are their units?
Stress is tension per unit cross-sectional area, has the unit Pa (pascal)
Strain is extension per unit length, has no unit because it is a ratio
Describe a velocity-time and speed-time graph and what information can be found
Velocity-time graph:
- The area underneath is the displacement (distance from start point)
- The gradient represents the acceleration of the object
Speed-time graph
- The area underneath is the distance travelled
- The acceleration can be worked out using change in speed divided by time
