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Nuclear fuel is a non-renewable resource because it uses uranium or plutonium, which are finite resources that cannot be replenished as they are used. Geothermal, solar, and wind are renewable energy resources.

1 mark for correct answer B.

Use the equation: kinetic energy \(E_k = \frac{1}{2} m v^2\). Substituting the values: \(E_k = \frac{1}{2} \times 0.5\text{ kg} \times (4\text{ m/s})^2 = 0.25 \times 16 = 4\text{ J}\).

1 mark for correct answer C.

According to Ohm's law, at a constant temperature, the current through an ohmic conductor is directly proportional to the potential difference across it. This relationship is represented by a straight line that passes through the origin.

1 mark for correct answer A.

In a standard UK mains three-core cable, the live wire is brown, the neutral wire is blue, and the earth wire has green and yellow stripes.

1 mark for correct answer B.

Sublimation is the transition of a substance directly from the solid to the gas state without passing through the liquid state. Evaporation is liquid to gas, melting is solid to liquid, and condensation is gas to liquid.

1 mark for correct answer D.

Increasing the temperature of a gas increases the thermal energy store of the gas, which increases the average kinetic energy of its particles. Therefore, the particles move at higher average speeds.

1 mark for correct answer C.

Alpha radiation consists of helium nuclei which have a relatively large mass and a charge of \(+2\). This makes them highly interacting and the most strongly ionizing type of nuclear radiation compared to beta and gamma.

1 mark for correct answer A.

Isotopes are defined as atoms of the same element (meaning they have the exact same number of protons) that have different numbers of neutrons (which gives them different mass numbers).

1 mark for correct answer B.

Nuclear fuel is non-renewable because the uranium used is a finite resource, but it is reliable because it can produce electricity constantly regardless of weather conditions.

1 mark for correct answer C.

Temperature is a measure of the average kinetic energy of the particles in a substance. As the temperature increases, the average kinetic energy of the water molecules increases.

1 mark for correct answer B.

The neutral wire is blue, the live wire is brown, and the earth wire is green and yellow stripes.

1 mark for correct answer A.

A neutron is neutral and has a relative charge of \(0\). Protons have a relative charge of \(+1\) and electrons have a relative charge of \(-1\).

1 mark for correct answer B.

As the toy car is released and accelerates, the elastic potential energy stored in the wind-up spring decreases as it is transferred into the kinetic energy store of the car.

1 mark for correct answer B.

A thermistor is a temperature-dependent resistor. Its resistance decreases as the temperature increases.

1 mark for correct answer C.

Sublimation is the transition of a substance directly from the solid to the gas state, without passing through the liquid state.

1 mark for correct answer D.

Alpha radiation consists of helium nuclei which are highly ionising but have very low penetrating power, meaning they are easily stopped by paper or a few centimetres of air.

1 mark for correct answer A.

To find the increase in gravitational potential energy, use the equation: \(E_p = m \times g \times h\). Substitute the given values into the equation: \(E_p = 4.0\text{ kg} \times 9.8\text{ N/kg} \times 5.0\text{ m} = 196\text{ J}\). Therefore, the correct option is C.

1 mark for the correct option C (\(196\text{ J}\)).

To calculate the potential difference, use the equation: \(V = I \times R\). Substitute the values given in the question: \(V = 0.4\text{ A} \times 15\ \Omega = 6.0\text{ V}\). Therefore, the correct option is B.

1 mark for the correct option B (\(6.0\text{ V}\)).

The independent variable is the variable that is deliberately changed by the investigator, which is the length of the wire. The dependent variable is the variable that is measured for each change, which is the electrical resistance of the wire.

[1 mark] for correctly identifying the independent variable as the length (of the wire).
[1 mark] for correctly identifying the dependent variable as the resistance (of the wire).

The dependent variable is the variable that is measured, which is the time taken to heat the water. A control variable is something kept the same to ensure a fair test, such as the power of the heater, the temperature change, or the starting temperature of the water.

[1 mark] for identifying the dependent variable as the time taken.
[1 mark] for identifying a correct control variable (e.g., the temperature rise of 10 °C, the power of the heater, or the type of beaker).

The alpha scattering experiment showed that most alpha particles passed straight through the gold foil, indicating the atom is mostly empty space. A small number of alpha particles were deflected at large angles, leading to the conclusion that the mass is concentrated in a tiny, positively charged nucleus at the centre.

[1 mark] for each correct conclusion (up to 2):
- The atom is mostly empty space.
- The nucleus contains most of the atom's mass.
- The nucleus has a positive charge.
- The nucleus is extremely small compared to the size of the atom.

Using the equation: \(E_p = m \times g \times h\)
\(E_p = 12\text{ kg} \times 9.8\text{ N/kg} \times 4.0\text{ m} = 470.4\text{ J}\).

[1 mark] for correct substitution: \(12 \times 9.8 \times 4.0\)
[1 mark] for correct calculated answer of \(470.4\text{ J}\) (accept \(470\text{ J}\)).

The independent variable is the one changed by the student, which is the volume of the gas (by pushing the plunger). The dependent variable is the one measured, which is the pressure of the gas.

[1 mark] for identifying the independent variable as the volume (of the gas).
[1 mark] for identifying the dependent variable as the pressure (of the gas).

A renewable energy resource is replenished as quickly as it is used, meaning it will never run out. Examples include solar power, wind power, and wave power.

[1 mark] for explaining that it can be replenished as it is used (do not accept 'can be reused').
[1 mark] for a correct example (e.g. wind, solar, wave, tidal, biofuel, geothermal, hydroelectric).

The independent variable is what the student deliberately changes, which is the light intensity (or the distance of the lamp from the LDR). To make it a fair test, control variables such as the potential difference of the power supply or the temperature of the room must be kept constant.

[1 mark] for identifying the independent variable as light intensity (allow distance of the light source/lamp).
[1 mark] for identifying a correct control variable (e.g., potential difference of the power source / room temperature / background light level / same LDR).

During a change of state (melting), the temperature remains constant because the energy supplied is being used to break intermolecular bonds rather than increase kinetic energy. The thermal energy required to change the state of a substance is called latent heat.

[1 mark] for stating that the temperature remains constant / stays the same.
[1 mark] for identifying the energy as (specific) latent heat (of fusion).

The independent variable is the variable that is set or changed by the investigator, which in this case is the time (measured at 30-second intervals). The dependent variable is the variable that is measured to see how it changes, which is the temperature of the water.

1 mark for identifying the independent variable as time. 1 mark for identifying the dependent variable as temperature.

The independent variable is the factor that the investigator deliberately changes, which is the length of the wire. To ensure the test is fair and the results are valid, other variables affecting resistance must be kept constant. These control variables include the thickness (or cross-sectional area) of the wire, the material of the wire, and the temperature of the wire.

1 mark for identifying the independent variable as the length (of the wire). 1 mark for identifying a correct control variable, such as thickness, diameter, cross-sectional area, material, or temperature of the wire.

1. Identify the given values from the question:
- \(\text{mass} = 15\text{ kg}\)
- \(\text{speed} = 4.0\text{ m/s}\)

2. Substitute the values into the kinetic energy equation:
\(\text{kinetic energy} = 0.5 \times 15 \times (4.0)^2\)

3. Calculate the square of the speed:
\((4.0)^2 = 16\)

4. Complete the calculation:
\(\text{kinetic energy} = 0.5 \times 15 \times 16 = 120\text{ J}\)

1 mark: For substituting the correct values into the equation: \(0.5 \times 15 \times 4^2\)
1 mark: For completing the squaring of speed or showing an intermediate step: \(0.5 \times 15 \times 16\) or \(7.5 \times 16\)
1 mark: For the correct final answer of \(120\) (J)

1. Convert the time from minutes to seconds:
\(\text{time} = 2.0 \times 60 = 120\text{ s}\)

2. Substitute the current and converted time into the equation:
\(\text{charge flow} = 0.5\text{ A} \times 120\text{ s}\)

3. Calculate the final charge flow:
\(\text{charge flow} = 60\text{ C}\)

1 mark: For converting minutes to seconds: \(2 \times 60 = 120\text{ s}\)
1 mark: For substituting current and the calculated time into the equation: \(0.5 \times 120\)
1 mark: For the correct final answer of \(60\) (C)

1. Identify the values: \(\text{mass} = 60\text{ kg}\), \(g = 9.8\text{ N/kg}\), \(\text{height} = 5.0\text{ m}\).

2. Substitute the values into the equation:
\(\text{gravitational potential energy} = 60 \times 9.8 \times 5.0\)

3. Calculate the energy:
\(\text{gravitational potential energy} = 2940\text{ J}\)

1 mark: For substituting correct values into the equation: \(60 \times 9.8 \times 5\)
1 mark: For an intermediate calculation step, e.g., \(300 \times 9.8\) or \(588 \times 5\)
1 mark: For the correct final answer of \(2940\) (J)

1. Identify the values from the question: \(\text{mass} = 0.80\text{ kg}\), \(\text{volume} = 0.0016\text{ m}^3\).

2. Substitute these values into the density equation:
\(\text{density} = \frac{0.80}{0.0016}\)

3. Calculate the final density:
\(\text{density} = 500\text{ kg/m}^3\)

1 mark: For stating or selecting the correct density equation (implicit if correct substitution is shown)
1 mark: For substituting the correct values: \(\frac{0.80}{0.0016}\)
1 mark: For the correct final answer of \(500\) (kg/m³)

1. Identify the given values: \(\text{power} = 800\text{ W}\), \(\text{time} = 300\text{ s}\).

2. Substitute the values into the energy equation:
\(\text{energy transferred} = 800 \times 300\)

3. Calculate the total energy:
\(\text{energy transferred} = 240,000\text{ J}\) (or \(240\text{ kJ}\))

1 mark: For selecting/stating the correct equation (implicit if correct substitution is shown)
1 mark: For substituting the correct values: \(800 \times 300\)
1 mark: For the correct final answer of \(240,000\) (or \(240\text{ kJ}\))

1. Identify the given values:
- \(\text{change in thermal energy} = 18,000\text{ J}\)
- \(\text{mass} = 2.0\text{ kg}\)
- \(\text{temperature change} = 10\text{ }^\circ\text{C}\)

2. Substitute these values into the equation:
\(18,000 = 2.0 \times \text{specific heat capacity} \times 10\)

3. Simplify the right side of the equation:
\(18,000 = 20 \times \text{specific heat capacity}\)

4. Rearrange to find the specific heat capacity:
\(\text{specific heat capacity} = \frac{18,000}{20} = 900\text{ J/kg}^\circ\text{C}\)

1 mark: For substituting the values correctly into the equation: \(18,000 = 2.0 \times c \times 10\)
1 mark: For rearranging the equation: \(c = \frac{18,000}{20}\)
1 mark: For the correct final answer of \(900\) (J/kg°C)

1. Identify the values: \(\text{potential difference} = 6.0\text{ V}\), \(\text{current} = 0.15\text{ A}\).

2. Substitute the values into the equation:
\(6.0 = 0.15 \times \text{resistance}\)

3. Rearrange the equation to solve for resistance:
\(\text{resistance} = \frac{6.0}{0.15}\)

4. Calculate the final value:
\(\text{resistance} = 40\text{ }\Omega\)

1 mark: For substituting the values correctly: \(6.0 = 0.15 \times R\)
1 mark: For rearranging the equation to make R the subject: \(R = \frac{6.0}{0.15}\)
1 mark: For the correct final answer of \(40\) (Ω)

1. Find how many half-lives have passed in \(12\text{ hours}\):
\(\text{Number of half-lives} = \frac{12\text{ hours}}{4\text{ hours}} = 3\text{ half-lives}\)

2. Halve the initial activity three times sequentially:
- After \(1\text{ half-life (4 hours)}\): \(800 \div 2 = 400\text{ Bq}\)
- After \(2\text{ half-lives (8 hours)}\): \(400 \div 2 = 200\text{ Bq}\)
- After \(3\text{ half-lives (12 hours)}\): \(200 \div 2 = 100\text{ Bq}\)

3. The activity after \(12\text{ hours}\) is \(100\text{ Bq}\).

1 mark: For calculating the correct number of half-lives: \(12 \div 4 = 3\)
1 mark: For showing a clear process of halving the activity successively (e.g., \(800 \rightarrow 400 \rightarrow 200\))
1 mark: For the correct final answer of \(100\) (Bq)

Step 1: Convert the time from minutes to seconds.
\[t = 4\text{ minutes} = 4 \times 60\text{ seconds} = 240\text{ s}\]

Step 2: Use the equation linking charge flow, current, and time:
\[\text{charge flow} = \text{current} \times \text{time}\]
\[Q = I \times t\]

Step 3: Substitute the values into the equation:
\[Q = 0.6\text{ A} \times 240\text{ s} = 144\text{ C}\]

- **[1 mark]** Correct conversion of time from minutes to seconds: \(4 \times 60 = 240\text{ (s)}\).
- **[1 mark]** Correct substitution of their converted time and the current into the equation: \(Q = 0.6 \times 240\).
- **[1 mark]** Correct final answer of \(144\).

*Note: An answer of 2.4 (arising from failure to convert minutes to seconds) scores 1 mark maximum (for correct substitution).*
*An answer of 144 without working scores full marks.*

To determine the specific heat capacity of an aluminium block, the student needs to measure the mass of the block, the temperature change, and the energy supplied.

**Apparatus:**
* Aluminium block with two pre-drilled holes
* Electronic balance
* Thermometer
* Electric immersion heater
* Low-voltage power supply
* Joulemeter (or an ammeter, voltmeter, and stopwatch)
* Insulating material (such as bubble wrap or cotton wool)

**Method:**
1. Measure and record the mass of the aluminium block using the electronic balance.
2. Wrap the block tightly in the insulating material to reduce energy transfers to the surroundings.
3. Place the heater in one hole and the thermometer in the other hole of the block.
4. Measure and record the initial temperature of the block.
5. Turn on the power supply and start the joulemeter.
6. Leave the heater on for a set time (e.g., 10 minutes) to allow a significant temperature rise.
7. Turn off the power supply and record the final maximum temperature reached on the thermometer.
8. Record the total energy supplied from the joulemeter reading.

**[1 mark]** Measure and record the mass of the aluminium block using an electronic balance.
**[1 mark]** Wrap the block in insulating material (to reduce heat loss to the surroundings).
**[1 mark]** Measure and record the initial and final temperature of the block using a thermometer.
**[1 mark]** Use an electric heater connected to a power supply and a joulemeter to supply energy.
**[1 mark]** Record the energy input from the joulemeter (or measure potential difference, current, and time to calculate energy using \(E = V \times I \times t\)).

**How pressure is exerted:**
Gas particles are in constant, rapid, and random motion. As they move, they collide with the inside walls of the metal canister. Each individual collision exerts a tiny force on the wall. The cumulative force of all these collisions over the internal surface area of the canister creates gas pressure, where pressure is force per unit area (\(p = F / A\)).

**Why temperature increases pressure:**
When the gas is heated, the particles gain kinetic energy and move faster. Because they are moving faster, two things happen:
1. They collide with the walls of the canister more frequently (more often per second).
2. They collide with greater force (each impact is harder).
These factors increase the total overall force exerted on the walls, which increases the pressure.

**[1 mark]** Gas particles are in constant, random motion and collide with the inside walls of the canister.
**[1 mark]** Each collision exerts a force on the wall (which results in pressure over the area).
**[1 mark]** Increasing the temperature increases the kinetic energy / speed of the gas particles.
**[1 mark]** The faster-moving particles collide with the walls more frequently (more collisions per second).
**[1 mark]** The particles collide with the walls with greater force / harder (increasing the overall pressure).

Displacement is a vector quantity because it has both magnitude and direction. Speed, distance, and mass only have magnitude, so they are scalar quantities.

1 mark for the correct option (C).

In a longitudinal wave (such as a sound wave), the oscillations of the particles are parallel to the direction in which the wave travels (energy transfer).

1 mark for the correct option (B).

Magnetic materials placed in a magnetic field experience induced magnetism. This always results in an attractive force, so the pole closest to the permanent magnet's north pole must be an induced south pole.

1 mark for the correct option (B).

Hooke's Law states that the extension of an elastic object is directly proportional to the force applied to it, provided its limit of proportionality is not exceeded.

1 mark for the correct option (B).

The electromagnetic spectrum in order of increasing wavelength (shortest to longest) is: Gamma rays, X-rays, Ultraviolet, Visible light, Infrared, Microwaves, Radio waves. Thus, Gamma rays, X-rays, Ultraviolet, Radio waves is correct.

1 mark for the correct option (B).

Using Newton's Second Law: \(F = m \times a\). Rearranging for acceleration gives \(a = \frac{F}{m} = \frac{2.0\text{ N}}{0.5\text{ kg}} = 4.0\text{ m/s}^2\).

1 mark for the correct option (C).

In Fleming's left-hand rule, the First finger represents the direction of the magnetic Field, the seCornd finger represents the direction of the Current, and the thuMb represents the direction of the Motion (force).

1 mark for the correct option (A).

Thinking distance is the distance travelled during the driver's reaction time. Factors like tiredness, drugs, alcohol, or distractions increase reaction time and therefore increase thinking distance. Wet roads, worn brakes, and worn tyres affect the braking distance.

1 mark for the correct option (C).

All electromagnetic waves travel at the same speed (the speed of light, \(3 \times 10^8\text{ m/s}\)) through a vacuum.

1 mark for the correct answer: c.

Iron is a magnetic material (along with steel, cobalt, and nickel) and is attracted to magnets. Aluminium, copper, and zinc are non-magnetic.

1 mark for the correct answer: c.

Using the equation: \(\text{speed} = \frac{\text{distance}}{\text{time}}\), we get \(\text{speed} = \frac{12\text{ m}}{3\text{ s}} = 4\text{ m/s}\).

1 mark for the correct answer: b.

The Sun is at the centre of our solar system, and all the planets and other bodies orbit around it.

1 mark for the correct answer: c.

Inelastic deformation occurs when an object has been stretched beyond its limit of proportionality and does not return to its original shape/length when the forces are removed.

1 mark for the correct answer: b.

Sound waves are longitudinal waves. Radio waves, light waves, and water waves are all transverse waves.

1 mark for the correct answer: b.

Red-shift is an increase in the wavelength of light from distant galaxies, moving the observed light towards the red end of the spectrum.

1 mark for the correct answer: c.

Matt black surfaces are the best absorbers and the best emitters of infrared radiation. Shiny surfaces are poor absorbers and poor emitters (they are good reflectors).

1 mark for the correct answer: c.

Overexposure to ultraviolet (UV) radiation is dangerous to human health. It can cause damage to skin cells, leading to sunburn and premature ageing of the skin. It also increases the risk of developing skin cancers (such as melanoma) and can damage the eyes, leading to cataracts.

Award 1 mark for each correct risk (maximum of 2 marks):
- Sunburn / skin burns
- Premature ageing of the skin
- Skin cancer
- Cataracts / eye damage
(Do not accept generic terms like 'harm' or 'damage' without qualification).

The extension \(e\) of the spring is calculated by subtracting the original unstretched length from the final stretched length:
\(e = 0.14\text{ m} - 0.08\text{ m} = 0.06\text{ m}\).

1 mark for the correct calculation method: \(0.14 - 0.08\)
1 mark for the correct final value with unit: \(0.06\text{ m}\) (accept \(6\text{ cm}\)).

1. Place the plotting compass near one pole of the bar magnet and mark dots at both ends of the compass needle.
2. Move the compass so that the rear end of the needle points to the second dot, and mark a new dot at the front of the needle.
3. Repeat this process until you reach the other pole of the magnet, and then join the dots with a smooth line to show the magnetic field line.

1 mark for placing the compass and marking the position of the needle with dots.
1 mark for moving the compass along to a new position (tail on the previous dot) and joining the dots to draw the field line.

Using the wave equation:
\(\text{wave speed} = \text{frequency} \times \text{wavelength}\)
\(\text{wave speed} = 5.0\text{ Hz} \times 0.40\text{ m} = 2.0\text{ m/s}\).

1 mark for substitution: \(5.0 \times 0.40\)
1 mark for correct evaluation: \(2.0\text{ m/s}\) (accept \(2\) or \(2.0\)).

A scalar quantity is described completely by its magnitude (size) alone. A vector quantity requires both a magnitude and a specific direction to be fully described. Examples of vector quantities include force, weight, velocity, displacement, and acceleration.

1 mark for stating that a scalar has magnitude only, while a vector has magnitude and direction.
1 mark for any correct vector quantity example (e.g., force, velocity, displacement, acceleration, momentum, weight).

Rearranging the equation for speed:
\(\text{speed} = \frac{\text{distance travelled}}{\text{time}}\)
\(\text{speed} = \frac{150\text{ m}}{10\text{ s}} = 15\text{ m/s}\).

1 mark for rearranging the equation or substituting: \(\frac{150}{10}\)
1 mark for the correct answer: \(15\text{ m/s}\) (or \(15\)).

A natural satellite (such as a moon) is a naturally occurring astronomical body that orbits a planet, whereas an artificial satellite is a man-made device built by humans and launched into orbit. The Moon is the Earth's only natural satellite.

1 mark for stating that natural satellites are naturally occurring while artificial satellites are human-made.
1 mark for stating the Moon as the Earth's natural satellite.

Every wave in the electromagnetic spectrum travels through a vacuum at the exact same speed, which is the speed of light (\(3.0 \times 10^8\text{ m/s}\)). Additionally, all electromagnetic waves are transverse waves, meaning their oscillations are perpendicular to the direction of energy transfer.

Award 1 mark for each correct property (maximum of 2 marks):
- They travel at the same speed (speed of light)
- They are all transverse waves
- They can travel through a vacuum / do not require a medium to travel

To find the average speed, substitute the values of distance and time into the given equation:

\(\text{speed} = \frac{18}{6}\)

\(\text{speed} = 3\text{ m/s}\)

- **1 mark**: For correct substitution of values into the equation: \(\frac{18}{6}\)
- **1 mark**: For the correct value: \(3\) (m/s)

All electromagnetic waves travel at the same speed through a vacuum (which is \(3 \times 10^8\text{ m/s}\), the speed of light). In addition, they are all transverse waves.

- **1 mark**: For stating that they travel at the same speed / the speed of light.
- **1 mark**: For stating that they are all transverse waves (accept: they can all travel through a vacuum).

When a magnetic material like an iron nail is placed in a magnetic field, it becomes a magnet itself. This is called induced magnetism. The induced pole nearest the permanent magnet is always opposite to the pole of the permanent magnet, so the iron nail is always attracted to the bar magnet.

- **1 mark**: For stating that the iron nail is attracted to the magnet (or moves towards it).
- **1 mark**: For identifying the type of magnetism as 'induced' magnetism.

First, rearrange the equation to make extension the subject:

\(\text{extension} = \frac{\text{force}}{\text{spring constant}}\)

Now substitute the given values into the equation:

\(\text{extension} = \frac{5}{25} = 0.2\text{ m}\)

- **1 mark**: For correct rearrangement or correct substitution of values: \(5 = 25 \times \text{extension}\) or \(\frac{5}{25}\)
- **1 mark**: For the correct final value: \(0.2\) (m) (accept \(20\text{ cm}\) if unit is clearly stated as cm)

First, determine the change in velocity:
\(\text{change in velocity} = 18\text{ m/s} - 0\text{ m/s} = 18\text{ m/s}\).

Next, substitute the values into the equation:
\(\text{acceleration} = \frac{18}{6.0}\)

\(\text{acceleration} = 3.0\text{ m/s}^2\).

1 mark for calculating the change in velocity as \(18\text{ m/s}\) or substituting correct values into the equation: \(\frac{18}{6.0}\).
1 mark for the correct calculation: \(3.0\) (or \(3\)).
1 mark for the correct unit: \(\text{m/s}^2\).

Substitute the values into the wave equation:
\(\text{wave speed} = (2.0 \times 10^5) \times 1500\)

\(\text{wave speed} = 300,000,000\text{ m/s}\) or \(3.0 \times 10^8\text{ m/s}\).

1 mark for correct substitution: \((2.0 \times 10^5) \times 1500\).
1 mark for correct calculation: \(3.0 \times 10^8\) (or \(300,000,000\)).
1 mark for correct unit: \(\text{m/s}\).

Substitute the values into the equation:
\(\text{force} = 25\text{ N/m} \times 0.12\text{ m}\)

\(\text{force} = 3.0\text{ N}\).

1 mark for correct substitution: \(25 \times 0.12\).
1 mark for correct calculation: \(3.0\) (or \(3\)).
1 mark for correct unit: \(\text{N}\) (or Newtons).

Rearrange the equation to make distance the subject:
\(\text{distance} = \frac{\text{work done}}{\text{force}}\)

Substitute the given values into the equation:
\(\text{distance} = \frac{340}{85}\)

\(\text{distance} = 4.0\text{ m}\).

1 mark for correct rearrangement of the equation or correct substitution: \(340 = 85 \times \text{distance}\).
1 mark for correct calculation: \(4.0\) (or \(4\)).
1 mark for correct unit: \(\text{m}\) (or metres).

Rearrange the equation to make frequency the subject:
\(\text{frequency} = \frac{\text{wave speed}}{\text{wavelength}}\)

Substitute the values into the equation:
\(\text{frequency} = \frac{0.80}{0.04}\)

\(\text{frequency} = 20\text{ Hz}\).

1 mark for correct rearrangement or correct substitution: \(0.80 = \text{frequency} \times 0.04\).
1 mark for correct calculation: \(20\).
1 mark for correct unit: \(\text{Hz}\) (or hertz).

Substitute the given values into the equation:
\(\text{weight} = 80\text{ kg} \times 1.6\text{ N/kg}\)

\(\text{weight} = 128\text{ N}\).

1 mark for correct substitution: \(80 \times 1.6\).
1 mark for correct calculation: \(128\).
1 mark for correct unit: \(\text{N}\) (or Newtons).

Rearrange the equation to make acceleration the subject:
\(\text{acceleration} = \frac{\text{resultant force}}{\text{mass}}\)

Substitute the values into the equation:
\(\text{acceleration} = \frac{4.5}{1.5}\)

\(\text{acceleration} = 3.0\text{ m/s}^2\).

1 mark for correct rearrangement or correct substitution: \(4.5 = 1.5 \times \text{acceleration}\).
1 mark for correct calculation: \(3.0\) (or \(3\)).
1 mark for correct unit: \(\text{m/s}^2\).

Substitute the values into the equation:
\(\text{moment} = 30\text{ N} \times 0.25\text{ m}\)

\(\text{moment} = 7.5\text{ N m}\).

1 mark for correct substitution: \(30 \times 0.25\).
1 mark for correct calculation: \(7.5\).
1 mark for correct unit: \(\text{Nm}\) (or Newton-metres).

To calculate the wave speed, use the formula:
\(\text{wave speed} = \text{frequency} \times \text{wavelength}\)

Substitute the given values into the formula:
\(\text{wave speed} = 4.5 \times 2.0\)

Calculate the final speed:
\(\text{wave speed} = 9\text{ m/s}\)

- 1 mark for substituting the values correctly: \(4.5 \times 2.0\)
- 1 mark for the correct calculated speed: \(9\)
- 1 mark for the correct unit: \(\text{m/s}\) (accept 'metres per second')

To calculate the work done, use the formula:
\(\text{work done} = \text{force} \times \text{distance}\)

Substitute the values from the question into the formula:
\(\text{work done} = 35 \times 6.0\)

Calculate the work done:
\(\text{work done} = 210\text{ J}\)

- 1 mark for substituting the correct values: \(35 \times 6.0\)
- 1 mark for the correct calculation: \(210\)
- 1 mark for the correct unit: \(\text{J}\) (accept 'Joules' or 'joules')

To carry out the investigation:
1. Set up a clamp stand with a boss and clamp. Hang the spring from the clamp.
2. Fix a metre ruler vertically next to the spring using a second clamp, ensuring the zero mark is at the top of the spring.
3. Attach a pointer (pointer/splint) horizontally to the bottom of the spring.
4. Measure the initial position of the pointer on the ruler (the unstretched length) when no weights are attached. Read at eye level to avoid parallax error.
5. Hang a standard weight (e.g. 1.0 N) from the bottom of the spring.
6. Record the new position of the pointer on the ruler.
7. Calculate the extension using the formula: \(\text{extension} = \text{new length} - \text{initial length}\).
8. Add further weights one at a time (e.g. up to 5.0 N), recording the new length and calculating the extension for each total force applied.

This is a 5-mark level of response question.

**Level 2 (3-5 marks):**
A detailed and coherent description of a workable method is provided. Clear steps are given to show how the apparatus is set up, how measurements are taken accurately (including reference to a vertical ruler/pointer/eye-level readings), and how the extension is calculated and varied with different weights.

**Level 1 (1-2 marks):**
A simple method is described. Key steps or apparatus are identified, but lacks detail on how to ensure accuracy or how extension is calculated from the length measurements.

**0 marks:**
No relevant content.

**Indicative content to look for:**
- Hang the spring from a clamp stand.
- Set up a ruler vertically next to the spring.
- Record the starting length / zero position of the bottom of the spring.
- Add known masses / weights to the spring.
- Measure the new length / position of the spring.
- Calculate extension = stretched length \(-\) original length.
- Repeat for a range of different weights.
- Accuracy detail: Use a pointer at the bottom of the spring, make sure ruler is vertical, or read at eye level to avoid parallax error.

To compare the absorption of infrared radiation:
1. Use two identical metal plates: one painted matte black and the other shiny silver.
2. Fix a thermometer or temperature sensor to the back of each plate.
3. Place an infrared heater (radiant heater) exactly halfway between the two plates, so they are both the same distance from the heat source.
4. Record the starting temperature of both plates to ensure they are at the same initial temperature.
5. Turn on the infrared heater and start a stopwatch.
6. Measure and record the temperature of both plates at regular intervals (e.g. every minute) for 10 minutes.
7. Compare the temperature increases. The plate with the higher final temperature (or the largest temperature increase) is the better absorber. (The matte black plate will have the higher temperature rise).

This is a 5-mark level of response question.

**Level 2 (3-5 marks):**
A logical and detailed method is described. The equipment is clearly identified, control variables (fair testing) are explained, and a clear explanation of how the measurements are used to determine the better absorber is provided.

**Level 1 (1-2 marks):**
A basic method is outlined. Mention is made of using two different surfaces and measuring temperature, but may lack details on control variables or how the comparison is made.

**0 marks:**
No relevant content.

**Indicative content to look for:**
- Use of two surfaces: matte black and shiny silver (or flasks painted black and silver).
- Use of a heat source (infrared lamp/heater).
- Placing both surfaces/flasks at the same distance from the heater.
- Measuring the initial temperature.
- Leaving the heater on for a set amount of time / measuring temperature at regular intervals.
- The surface that shows the larger temperature increase is the better absorber.
- Control variables: same size/material of plates, same starting temperature, same distance from the heat source.