Physics Notes

9702-P2_definition_bank

11 min read

1. Physical Quantities and Units

1.1 Precision

Success

9702_s17_qp_22 - Q1.c.ii

Question:

  • State what is meant by precision.

Answer:

  • Precision is determined by the range in the measurements/values/readings/data/results.
  • [a] A small range corresponds to high precision
  • [a] A large range corresponds to low precision

Success

9702_s20_qp_23 - Q1.b

Question:

  • A student takes several measurements of the same quantity. This set of measurements has high precision. State what is meant by high precision.

Answer:

  • The measurements have a small range.

Success

9702_w20_qp_21 - Q4.b.iv

Question:

  • Each student in the class performs the experiment and the teacher describes the values of the young modulus calculated by the students as having high accuracy and low precision. Explain what is meant by low precision.

Answer:

  • The values have a large range.

1.2 Accuracy

Success

9702_m25_qp_22 - Q1.a

Question:

  • Explain what is meant by the accuracy of a measured value.

Answer:

  • How close the measured value is to the true value of the quantity.

1.3 Scalar and Vector Quantities

Success

9702_s18_qp_21 - Q1.a

Question:

  • State what is meant by a scalar quantity and by a vector quantity

Answer:

  • A scalar quantity has magnitude only
  • A vector quantity has both magnitude and direction

2. Kinematics

2.1 Displacement

Success

9702_s24_qp_23 - Q2.a

Question:

  • Define displacement from a point.

Answer:

  • Distance from the point in a straight line in a given direction

2.2 Velocity

Success

9702_s25_qp_23 - Q1.a

Question:

  • Define velocity.

Answer:

  • Rate of change of displacement.

2.3 Acceleration

Success

9702_s25_qp_21 - Q1.a

Question:

  • Define acceleration.

Answer:

  • Rate of change of velocity.

3. Dynamics

3.1 Mass

Tip

Syllabus 2025-2027

Question:

  • State what is meant by the mass of a body.

Answer:

  • Mass is the property of an object that resists change in motion

3.2 Force

Success

9702_m25_qp_22 - Q3.b.i

Question:

  • Define force.

Answer:

  • Rate of change of momentum

3.3 Linear Momentum

Success

9702_w24_qp_21 - Q2.a

Question:

  • Define momentum ( or linear momentum).

Answer:

  • Product of mass and velocity.

3.4 Elastic Collision

Success

9702_s16_qp_23 - Q5.b.i

Question:

  • Explain what is meant by the particles colliding elastically.

Answer:

  • Total kinetic energy before the collision is equal to total kinetic energy after the collision.
  • [a] Relative speed of approach = Relative speed of separation

4. Forces, Density and Pressure

4.1 Centre of Gravity

Success

9702_s13_qp_22 - Q3.a (1 mark) 9702_w20_qp_23 - Q2.a (2 marks)

Question:

  • State what is meant by the centre of gravity of a body/object.

Answer:

  • Point where all the weight of the body/object (M1)
  • Is considered to act (A1)

4.2 Moment of a Force

Success

9702_s25_qp_24 - Q1.a (1 mark) 9702_s21_qp_23 - Q3.a (2 marks)

Question:

  • Define the moment of a force.

Answer:

  • Product of force and perpendicular distance from line of action of force to a point acting as pivot

Force x Distance only 1 mark (M1) Force x Perpendicular distance another mark for perpendicular (A1)

4.3 Torque of a Couple

Success

9702_w13_qp_21 - Q4.a

Question:

  • Define torque of a couple.

Answer:

  • Product of one of the forces and perpendicular distance between the forces.

Force x Distance only 1 mark (M1) Force x Perpendicular distance another mark for perpendicular (A1)

4.4 Equilibrium

Success

9702_s12_qp_21 - Q3.a

Question:

  • The mass is in equilibrium. Explain, b reference to the forces acting on the mass, what is meant by equilibrium.

Answer:

  • Resultant moment about any point = 0
  • Resultant force in any direction = 0

4.5 Density

Success

9702_w24_qp_21 - Q1.a

Question:

  • Define density.

Answer:

  • Mass per unit volume.

4.6 Pressure

Success

9702_s23_qp_22 - Q1.a.i

Question:

  • Define pressure.

Answer:

  • Force acting normally per unit area.

5. Work, Energy and Power

5.1 Work Done

Success

9702_w24_qp_21 - Q3.a

Question:

  • State what is meant by work done by a force.

Answer:

  • Product of force and displacement in direction of force

5.2 Power

Success

9702_s25_qp_21 - Q3.a

Question:

  • Define power.

Answer:

  • Work done per unit time.

5.3 Potential Energy

Success

9702_w07_qp_2 - Q3.a.i

Question:

  • Define potential energy.

Answer:

  • Stored energy available to do work.

Success

9702_w18_qp_21 - Q3.a.ii

Question:

  • State what is meant by gravitational potential energy.

Answer:

  • Energy of a mass due to its position in a gravitational field.

5.4 Kinetic Energy

Success

9702_w18_qp_23 - Q2.a

Question:

  • State what is meant by kinetic energy.

Answer:

  • Energy of a mass due to motion

6. Deformation of Solids

6.1 Stress

Success

9702_w24_qp_23 - Q4.a

Question:

  • Define stress.

Answer:

  • Force acting normally per unit cross sectional area.

6.2 Strain

Success

9702_w24_qp_23 - Q4.a

Question:

  • Define Strain.

Answer:

  • Extension per unit original length.

6.3 Young Modulus

Success

9702_s25_qp_22 - Q5.a

Question:

  • Define the Young Modulus.

Answer:

  • The ratio of stress to strain.

6.4 Elastic Deformation

Success

9702_s13_qp_21 - Q1.a

Question:

  • Explain what is meant by extended elastically.

Answer:

  • The wire returns to its original length (not shape!)
  • when the load is removed

Original shape is not accepted because it could be argued that the wire’s shape does not change when it extends as it remains a cylinder with roughly the same cross section.

6.5 Plastic Deformation

Success

9702_w12_qp_21 - Q5.a

Question:

  • Explain what is meant by plastic deformation.

Answer:

  • When load is removed the body does not return to its original shape

Here shape is accepted (size is also accepted but shape is better). This is because when an object such as a lump of clay or wire undergoes plastic deformation, it gets bent, squished, flattened, etc. For example, a lump of clay stops being a lump and a wire thins out, therefore, the shape changes.

6.6 Elastic Potential Energy

Success

9702_s16_qp_21 - Q4.a

Question:

  • State what is meant by elastic potential energy.

Answer:

  • The energy stored in a bod due to its deformation.

7. Waves

7.1 Progressive Wave

Success

identifier

Question:

  • State what is meant by a progressive wave.

Answer:

  • A wave that propagates energy.

7.2 Displacement

Success

9702_s19_qp_22 - Q4.a

Question:

  • For a progressive water wave, state what is meant by displacement.

Answer:

  • Distance in a specified direction of a point on the wave from the equilibrium position.

7.3 Amplitude

Success

9702_w21_qp_23 - Q5.a

Question:

  • For a progressive wave on a stretched string state what is meant by amplitude.

Answer:

  • Maximum displacement of a point on the wave from the equilibrium position.

7.4 Period

Success

9702_s21_qp_22 - Q4.a

Question:

  • For a progressive wave, state what is meant by its period.

Answer:

  • Time for one complete oscillation of a point on the wave.

7.5 Frequency

Success

9702_s23_qp_23 - Q4.a

Question:

  • For a progressive wave, state what is meant by the frequency.

Answer:

  • The number of oscillations per unit time of a point on the wave

7.6 Wavelength

Success

9702_s21_qp_21 - Q4.a

Question:

  • For a progressive wave, state what is meant by wavelength.

Answer:

  • Minimum distance between two points oscillating in phase

No marks awarded if ‘Minimum’ not seen in answer

7.7 Intensity

Tip

Textbook + other sources

Question:

  • For a progressive wave, state what is meant by intensity.

Answer:

  • Power per unit area perpendicular to the direction of propagation of energy.

7.8 Transverse wave

Success

9702_m24_qp_22 - Q5.a

Question:

  • By reference to the direction of propagation of energy, state what is meant by a transverse wave.

Answer:

  • Oscillations are perpendicular to the direction of propagation of energy

7.9 Longitudinal Wave

Success

9702_w21_qp_21 - Q4.a

Question:

  • By reference to the direction of transfer of energy, state what is meant by a longitudinal wave.

Answer:

  • Oscillations are parallel to the direction of energy transfer/propagation of energy Here, it is slightly better to use the term “energy transfer” instead of “propagation of energy” since the question mentioned “transfer of energy”.

7.10 Doppler Effect

Success

9702_m17_qp_22 - Q4.a

Question:

  • State what is meant by the Doppler Effect.

Answer:

  • Change in observed frequency when a source moves relative to the observer

7.11 Polarisation

Success

9702_w11_qp_23 - Q5.b

Question:

  • Describe what is meant by a polarised wave.

Answer:

  • A wave in which the oscillations are restricted to a single plane

Superposition

8.1 Stationary Wave

Tip

Textbook + other sources

Question:

  • Explain what is meant by a stationary wave.

Answer:

  • A wave in which there is no net transfer of energy.

8.2 Node

Success

9702_s20_qp_22 - Q4.c.i

Question:

  • Explain what is meant by a node of a stationary wave..

Answer:

  • A point on a stationary wave where the amplitude is zero.

8.3 Antinode

Success

9702_s18_qp_22 - Q4.a.ii

Question:

  • State what is meant by an antinode of a stationary wave.

Answer:

  • A point on a stationary wave where the amplitude is maximum.

8.4 Diffraction

Success

9702_w23_qp_22 - Q5.b

Question:

  • State what is meant by the diffraction of a wave.

Answer:

  • The spreading of the wave into its geometrical shadow
  • as it passes through an aperture or around an obstacle

8.5 Superposition

Success

9702_m19_qp_22 - Q5.a.i

Question:

  • Explain what is meant by the principle of superposition.

Answer:

  • When two waves overlap at a point
  • The resultant displacement is the sum of the displacement of each wave.

8.6 Coherence

Success

9702_s23_qp_21 - Q5.b.i

Question:

  • The light waves emerging from the two slits are coherent. State what is meant by coherent.

Answer:

  • Constant phase difference between the waves.

9. Electricity

9.1 Electric Current

Success

9702_w17_qp_22 - Q6.a

Question:

  • State what is meant by electric current.

Answer:

  • Rate of flow of charge carriers.

9.2 Electric Charge

Success

9702_s13_qp_22 - Q6.a

Question:

  • Define charge.

Answer:

  • Product of electric current and time

9.3 Potential Difference

Success

9702_s25_qp_22 - Q6.a

Question:

  • Define potential difference across a component.

Answer:

  • Energy transferred to the component per unit charge.
  • [a] Energy is converted from electrical to other forms

9.4 Resistance

Success

9702_w24_qp_23 - Q6.a

Question:

  • Define resistance.

Answer:

  • Potential difference per unit current.

10. D.C. Circuits

10.1 Electromotive Force

Success

9702_s21_qp_23 - Q5.a

Question:

  • Define the electromotive force of a source.

Answer:

  • Energy transferred from other forms to electrical energy
  • per unit charge

10.2 Null method

Success

9702_s25_qp_23 - Q7.b.i

Question:

  • Explain what is meant by a null method.

Answer:

  • A method where the reading on the galvanometer is zero

11. Particle Physics

11.1 Alpha particle

Success

9702_s10_qp_22 - Q7.a.i

Question:

  • State what is meant by an alpha particle.

Answer:

  • A helium nucleus

11.2 Isotopes

Success

9702_s10_qp_21 - Q7.a

Question:

  • State what is meant by isotopes.

Answer:

  • Atoms of the same element having the same proton number
  • But different number of neutrons

11.3 Radioactive Decay

Success

9702_w10_qp_23 - Q9.a

Question:

  • Explain what is meant by radioactive decay.

Answer:

  • Nucleus emits -particles or -particles and/or -radiation
  • to form a different more stable nucleus.

11.4 Fundamental Particle

Success

9702_s25_qp_22 - Q7.a

Question:

  • State what is meant by a fundamental particle.

Answer:

  • A particle that cannot be subdivided into smaller particles.

11.5 Spontaneous Decay

Success

9702_w09_qp_22

Question:

  • Explain what is meant by the spontaneous nature of decay.

Answer:

  • The decay is not affected by external factors (e.g., temperature, pressure).

11.6 Random Decay

Success

9702_w08_qp_2

Question:

  • Explain what is meant by the random nature of decay.

Answer:

  • It is impossible to predict which nucleus will decay next.
  • OR: It is impossible to predict when a specific nucleus will decay.
  • OR: There is a constant probability of decay per unit time.

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