very important things to remember for paper 1

What happens when cells/batteries are in parallel?

- voltage stays the same
- Internal resistance halves
- current available in circuit increases

What is electron capture the same as?

Beta plus

How do you know what should happen to proton number when it undergoes beta minus or plus decay?

Opposite of whatever the sign says

When, and only when, does TIR occur?

When the angle of incidence is greater than the critical angle

How could someone ensure a ray of light doesnt deviate from its intended path?

make the angle of incidence 0

When drawing a diffraction pattern you should…

Make sure the central maxima is noticeably wider than the other maxima, and also that the other maxima are the same width

2 ways a diffraction pattern is changed when a larger wavelength of light is used? (and vice versa)

Larger wavelength will cause:
1. Wider maxima
2. More spaced maxima

Identify how many moments are present in this diagram, for the anticlockwise and clockwise side

Anticlockwise there are 2 moments, 1 for the weight of the box and the length of the beam, 1 for the T of the rope and the length of the beam

Clockwise the only moment is the weight of the counterweight

How can you tell if an interaction is strong?

If its only between hadrons

What is the only interaction where strangeness DOESNT need to be conserved

Weak

How can you tell if an interaction is weak?

• change in quarks

• strangeness isnt conserved

• has leptons as well as hadrons

Whats a way you can find T for a pendulum system?

(Time taken for oscillations/Number of oscillations)

How can you, if asked to prove, show something to be increasing/decreasing exponentially?

Take a point on the graph and find how long it takes to half in value, repeat this again for a different point and if it takes the same amount of time, the graph is exponential

Whats a way for remembering which function to use to resolve a force

How would you find the magnitude of a resultant vector

sqrt(a²+b²)

How would you find the direction of a resultant vector?

tan^-1(vert/horz)

What does the gradient of an acceleration-time graph represent, firstly for a straight line graph, then a curved line?

Straight line - Gradient = constant acceleration
Curved line - Gradient at any tangential point = instantaneous rate of change of acceleration

What does the area underneath an acceleration-time graph represent?

Change in velocity

What does the gradient of a displacement-time graph represent?

Velocity

What does the area underneath a displacement-time graph represent?

Total displacement

What does the gradient of a velocity-time graph represent, firstly for a straight line graph, then a curved line?

Straight line - Gradient = Constant acceleration
Curved line - Gradient = Rate of change of acceleration

If an exam question uses the word ‘‘instantaneous’’ in reference to a graph, what does it mean you NEED to do?

A tangent is needed

For a pendulum swinging in SHM, Ek is max when ______
and minimum when _____

Max when at the amplitude
Minimum at the equilibrium position

For a pendulum swinging in SHM, GPE is at its max when _____
and at its minimum when _____

Max when at the equilibrium position
Minimum when at the amplitude

For a pendulum swinging in SHM, acceleration is at its max when _____
and at its minimum when _____

Max when at the amplitude
Minimum when at equilibrium position

For a mass-spring system in SHM, Ek is at its max when ____
and at its minimum when ____

Max at the equilibrium position
Minimum at amplitudes

For a mass-spring system in SHM, GPE is at its max when ____
and at its minimum when ____

Max at amplitude
Minimum at equilibrium

For a mass-spring system in SHM, GPE is at its max when ____
and at its minimum when ____

Max at equilibrium
And momentarily 0 at amplitude

What is Kirchoffs Current Law?

Total current entering a junction = Total current leaving a junction

What is Kirchoffs Voltage Law?

In a closed loop, the net change in voltage is 0

How would you convert the emf equation into the form of y = mx+c

ϵ = IR + Ir
ϵ = V +Ir
ϵ = Ir + V

Potential divider equation

V_out = V_in(R1/RT)

What is the antiparticle of the K⁰

Itself, K⁰

What are 2 possible quark configurations of π0

UU_
DD_

Are the K0 particle and the antiparticle variant the same thing?

No, the quark configurations are different
K0 —> ds_
K0_ —> d_s

What calculation can be done to find the number of electrons?

Current/Charge of electron

What is path difference the same as?

1 wavelength

As frequency decreases…

Wavelength increases, and vice versa

K+ —> π++ π0

When, and only when, should Youngs Double Slit equation be used?

When the slit separation is much much smaller than the the slit-to-screen distance

How do you convert kWh into Joules?

1kWh = 1000×3600 = 3.6×10^6 Joules

How do you convert Rads to degrees?

Rads(180/π)

How do you convert Rads to Revs

Revs = Rads/2π

What is the difference between Emission and Absorption?

Absorption is when an atom moves to higher energy via the absorption of a photon

Emission is when an atom moves to a lower energy state via the emission of a photon

1. Beta particles have a range of kinetic energies

2. There is a maximum amount of energy released so there must be another particle that carries the missing energy away

What is a rule for when strange particles are made?

They are always made in pair

How can you find mass per unit length?

density x area

What 2 equations are required in pretty much every single electricity equation?

V = IR
P = IV

What 3 things MUST be true in a series circuit?

1. Total PD is shared across components

2. Current is the same for all components

3. Total resistance = Sum of resistances

What 3 things MUST be true in a parallel circuit?

1. PD for each branch = PD of battery

2. Current is split between the branches

3. Adding more resistors in parallel REDUCES the total Resistance

When finding the total resistance of a circuit with internal resistance, what should you do?

You add the internal resistance onto whatever the parallel combo came out to be

R_tot = (1/R1 + 1/R2)^-1 + r

What is Rtot equal to in a circuit with internal resistance?

R_tot = R_parallel + R_internal

When during a weak interaction is it a W minus boson?

Up quark into Down quark

When during a weak interaction is it a W plus boson?

Down quark into Up quark