Required Recall (from all topics)

Question 1

PH1. State the seven base quantities and their units.

Answer 1

Distance (meters, m)
Time (seconds, s)
Luminous Intensity (Candela, Ca)
Mass (kilograms, kg)
Current (Amperes, A)
Temperature (Kelvin, K)
Amount of Substance (moles, mol)

Question 2

PH2. Define and state the units for every quantity listed on the formula sheet

Answer 2

Force (Newtons, N)
Energy (Joules, J)
Power (Watts, W)
Potential Difference (Volts, V
Resistance (Ohms, Ω)
Charge (Columns, C)
Power of Lens (Dioptres, D)
Frequency (Hertz, Hz)

Question 3

PH3. State equations to calculate areas, circumferences, surface areas, volumes of regular objects

Answer 3

Cuboids:

Spheres:

Cylinders:

Question 4

PH4. State equations to calculate areas, circumferences, surface areas, volumes of regular objects

Answer 4

Cuboids:
Area = w x h
Volume = w x h x d

Circles:
Circumference = 2πr
Area = πr²

Spheres:
Area = 4πr²
Volume= ⁴/₃πr³

Cylinders:
Surface area = 2hπr + 2πr²
Volume = 2πr²h

Question 5

ME1. State the definitions for scalar and vector quantities and give examples of each

Answer 5

Scalar Quantities only have magnitude.
Eg. mass, distance, speed

Vector Quantities have a magnitude and direction.
Eg. weight, displacement, velocity.

Question 6

ME2. Label the quantities shown by the slopes and areas of distance-time, velocity-time, and acceleration-time graphs

Answer 6

Distance-time graph:
Slope - Speed
Area - n/a

Velocity-time graph:
Slope - Acceleration
Area - Displacement

Acceleration-time graph:
Slope - n/a
Area - Change in Velocity

Question 7

ME3. Resolve a vector into two components at right angles to each other by calculation.

100N force, 50ᵒ from horizontal.

Answer 7

Y: 100Sin(50) = 76.6N
X: 100Cos(50) = 64.3N

Question 8

ME4. State Newton’s Laws of motion

Answer 8

1. An object at rest will remain at rest unless acted on by an unbalanced force.
   An object in motion will remain in motion unless acted on by an unbalanced force.
2. The acceleration of an object is directly proportional to the resultant force acting on it, and inversely proportional to its mass.
3. Every force has an equal, but opposite reaction force.

Question 9

ME5. State the properties of pairs of forces in an interaction between bodies

Answer 9

• Acting on the same objects.
• In opposite directions.
• With the same magnitude.
• And the same type of force.

Question 10

ME6. State the principle of conservation of linear momentum

Answer 10

The total momentum of an object before an event is equal to the total momentum of an object after momentum if linear momentum is conserved.

Question 11

ME7. State the definition of ‘the moment of a force’

Answer 11

The turning effect of a force.

Question 12

ME8. State the principle of conservation of energy

Answer 12

Energy cannot be created or destroyed only transferred from one object to another.

Question 13

EC1. State the definition for current

Answer 13

The rate of flow of charge.

Question 14

EC2. Derive the equations for combining resistances in series and parallel

Answer 14

The current through each resistor in series is the same: Iₜ = I₁ = I₂ = I₃
The total potential difference across the resistors is the sum of the potential differences across the separate resistors: Vₜ = V₁+ V₂+ V₃

Vₜ = IR

IₜRₜ = IₜR₁ + IₜR₂ + IₜR₃

(÷ Iₜ)

The total resistance is the sum of separate resistors: Rₜ = R₁ + R₂ + R₃

===============================

The potential difference across each resistor in parallel is the same: Vₜ = V₁ = V₂ = V₃

The current in the main circuit is the sum of the currents in each of the parallel branches: Iₜ = I₁ + I₂ + I₃

Iₜ=V/R

Vₜ/Rₜ = V₁/R₁ + V₂/R₂ + V₃/R₃

÷ Vₜ

The total resistance can be found through using Rₜ⁻¹ = R₁⁻¹ + R₂⁻¹ + R₃⁻¹

Question 15

EC3. Sketch current-potential difference graphs for ohmic conductors, filament bulbs, thermistors, and diodes

Answer 15

Google answer.

Ohmic Conductor:

• Straight line.
• Passing through the origin.

Filament Bulbs:

• S-shaped
• Centred through the origin.

Thermistors:
- Decreasing exponential.

Diode:

• At zero behind y-axis.
• Exponential growth.

Question 16

EC4. State the definition of electromotive force (e.m.f.)

Answer 16

The e.m.f. of a source is the amount of energy it supplies to one coulomb of charge.

Question 17

EC5. Draw and label a diagram of the structure of a metal

Answer 17

Google answer.

• Positive ions (bigger than electrons).
• Delocalised electrons (with a negative charge).
• Regular structure.

Question 18

MA1. Draw diagrams to show laminar and turbulent flow

Answer 18

Google answer.
- at least 5 lines

Laminar:

• Lines don’t cross.
• Moving in the same direction.

Turbulent:

• Lines crossing over.
• Conflicting directions.
• Som looping back on itself.

Question 19

MA2. State the conditions in which Stoke’s Law applies

Answer 19

• Small spherical objects.
• Moving at low speeds with laminar flow (or in the absence of turbulent flow).
• At constant temperature (viscosity is temperature dependent).

Question 20

MA3. State the relationship between upthrust and displaced fluid

Answer 20

Archimedes’ principle:

When a body is totally or partially immersed in a fluid, it experiences an upthrust equal to the weight of fluid displaced.

Question 21

MA4. Draw and label force-extension and force-compression graphs

Answer 21

• Where direct proportionality is obeyd (Hooke’s Law is applied)
• Point where direct proportionality ends (Limit of proportionality, Close to this is the elastic limit.).
• Point which the graph declines (Yield point)
• Elastic and plastic region labeled at the top.

-

Question 22

MA5. Define the terms limit of proportionality, elastic limit, yield point, elastic deformation and plastic deformation, and label these on force-extension/compression graphs

Answer 22

Limit of proportionality:
The is the point beyond which Hooke’s law no longer applies

Elastic limit:
The maximum extent to which a solid may be stretched without permanent alteration of size or shape.

Yield point:
The point beyond which a material becomes plastic.

Elastic Deformation:
The material will return to its original shape when the deforming force is removed.

Plastic Deformation;
The material will remain deformed when the deforming force is removed.

Question 23

MA6. Draw tensile or compressive stress-strain graphs

Answer 23

Slide 191.

Question 24

MA7. Label the quantities shown by the slopes and areas of a force-extension graph

Answer 24

Force-Extension:

Slopes: Spring constant
Area: Elastic strain energy

Question 25

WA1. State the definitions of transverse and longitudinal waves

Answer 25

Transverse: Waves that oscillate perpendicular to their direction of propagation.

Longitudinal: Waves that oscillate parallel to their direction of propagation.

Question 26

WA2. Draw and label graphs representing transverse and longitudinal waves

Answer 26

Displacement-Distance Graph:

• Sinusoidal graph.
• Can label on: Amplitude, Wavelength.

Displacement-Time Graph:

• Sinusoidal graph.
• Can label on: Amplitude, Period.

Question 27

WA3. State the definition of amplitude, wavefront, coherence, path difference, superposition, interference and phase

Answer 27

Amplitude: The magnitude of the maximum displacement reached by an oscillation in the wave.

Wavefront: Lines connecting points on the wave that are at exactly the same phase position.

Coherence: Waves with the same frequency and a constant phase relationship.

Path difference: The difference in the length of the paths that two waves take.

Superposition: Two or more waves meeting, resulting in there amplitudes summing.

Interference: Two or more waves meeting.

Phase: The position within a cycle that a given point occupies, relative to the onset of the cycle.

Question 28

WA4. State the definition of a standing/stationary wave, and identify nodes and antinodes

Answer 28

Waves with no net-movement, that store energy.

Nodes: Points on a stationary wave that don’t move.

Antinodes: Points on a stationary wave with maximum displacement.

Question 29

WA5. State the definitions of real and virtual images

Answer 29

Real: When rays actually intersect at a point.

Virtual: When rays don’t actually intersect at a point, but they appear to, when you look at the refracted rays.

Question 30

WA6. State the definition of plane polarisation and give examples of its use

Answer 30

Uses:
- Identification and analysis of optically active chemicals

• Liquid crystal displays
• Sunglasses and snow goggles
• TV and radio signals
• 3D film glasses

Question 31

WA7. State the definition of diffraction

Answer 31

When waves pass through a gap of similar size, causing it to split of in different directions.

Question 32

WA8. Draw a diagram of what happens when a wave meets a slit or obstacle using Huygen’s construction

Answer 32

Slide 119

Question 33

WA9. Describe diffraction experiments that provide evidence for the wave nature of electrons

Answer 33

• Electrons were fired through a slit.
• If they had particle properties they would only show one line where the electrons passed through
• However they observed diffraction patterns on the wall which told them electrons also have wave properties.

Question 34

WA10. Describe the pulse-echo technique used to find distance

Answer 34

• Short wavelengths of waves (of know wave speed) are fired at an object in short pulses.
• The pulse is timed from when it was fired to when it returns.
• This time is half to account for one direction of travel.
• The distance is calculated from the Speed-distance-time equation.