Edexcel A Level Physics Paper 3: General and Practical Principles in Physics June 2023 question paper 9PH0/03

A student used a laser pointer to direct monochromatic light normal to the plane of a diffraction grating as shown.

A diffraction pattern was produced on the screen. The distance between the first order maximum and the central maximum of the diffraction pattern was x. The distance between the diffraction grating and the screen was D.

The diffraction grating had 300 lines per mm. The laser pen was marked with λ = 520 nm.

Determine whether the spacing of the diffraction pattern was consistent with these values.

x = 43.5 cm D = 2.75 m

The student wrote the following conclusion:

“The value of x was measured with a metre rule. A metre rule has a precision of 0.1 cm, so this value was determined with a high degree of accuracy.”

Comment on this conclusion.

A battery has an e.m.f. of 12 V and an internal resistance of 0.50 Ω. The battery is connected into a circuit, as shown.

Each bulb has a normal working power of 40 W when a potential difference (p.d.) of 12 V is applied.

Initially the switch is open.

Calculate the terminal p.d. of the battery when bulb 1 is lit. Assume that the resistance of the bulb has its normal working value.

Terminal p.d. of battery =_........

Explain how the brightness of bulb 1 changes when the switch is closed. No further calculations are necessary.

A student planned to vary the current in the heater from 0 A to 5 A. The student connected the following circuit to measure the current in the heater.

Criticise the student’s circuit.

The student corrected the circuit and closed the switch. He waited until the water started boiling. He started a stopwatch and recorded the readings on the balance at regular time intervals.

Sketch a graph, on the axes below, of how the readings on the balance would vary with time.

The heater was switched on for 6.0 minutes and the change in mass of water in the beaker was 7.5 g.

Calculate the specific latent heat of vaporisation of water, L.

V = 12 V I = 4.2 A

The errors in the experiment include uncertainty in the mass reading and uncertainty in reading the stopwatch, as the water boils.

Explain how another significant source of error affects the value of L obtained from the experiment.

*4 Alpha particle scattering experiments led Rutherford to propose the nuclear model of the atom. Alpha particles were directed towards a thin gold foil.

Describe how evidence from these experiments supports the nuclear model of the atom.

Give one advantage of using a reference wire as well as a test wire.

State why a reference load was applied to the reference wire.

Explain why the test wire should be both long and thin.

The student varied the load F on the test wire and recorded the corresponding change in length Δ x from the vernier scale. The results are shown on the graph.

Δ x / mm

Determine a value for the Young modulus of brass.

length of wire = 2.75 m

A student investigated the horizontal oscillations of a trolley between two springs, using the apparatus shown.

The student displaced the trolley from its equilibrium position. She then released the trolley and started a stopwatch. She stopped the stopwatch when the trolley had completed one oscillation.

Describe how the method used by the student could be improved to determine a more accurate value of the time period.

The student displaced the trolley 6.0 cm from the equilibrium position. She recorded the velocity of the oscillating trolley using a sensor connected to a data logger.

The output from the data logger is shown below.

The time-base of the data logger output was set to 250 ms div^–1.

Determine the maximum velocity of the trolley.

Explain the shape of the graph.

Determine the effective spring constant k of the oscillating trolley system.

mass of trolley = 0.87 kg

The neon lamp shown is a glass bulb filled with neon gas at low pressure.

(Source: https://media.digikey.com/Photos/Visual%20Communications%20Company%20VCC/ A1A.JPG)

*(a) When in use, the neon gas between the electrodes emits electromagnetic radiation.

Explain why this happens when there is an electric current between the electrodes.

When light from the neon lamp is incident upon a metal surface, electrons with a maximum speed of 2.68 10⁵m s⁻¹ are emitted from the surface.

The table shows the work functions of some metals.

Deduce which metal the light is incident upon.

frequency of light from the neon lamp = 5.56 × 10¹⁴Hz

A student investigated the discharge of a capacitor C through a resistor R using the circuit shown.

The student used the switch to connect C to X to charge the capacitor. She then connected C to Y to discharge the capacitor through R.

As the capacitor discharged, she recorded values of the potential difference V across C and corresponding values of time t. She used a stopwatch to measure t.

The student used her results to plot the following graph.

The capacitor was marked 220 μF ± 20%.

Deduce whether the student’s data give a value of capacitance within the stated range.

R = 82 kΩ

The student suggested that her results would have been more accurate if she had used a data logger to record the data.

Assess the student’s suggestion.

A student investigated the behaviour of small, positively charged oil drops in an electric field.

He introduced an oil drop between two horizontal metal plates. A potential difference V was applied to bring the oil drop to rest as shown.

Add to the diagram to show the polarity of the power supply when the oil drop is at rest.

The oil drop was at rest when V = 4870 V.

The student expected the charge on the oil drop to be a whole number multiple of the charge on an electron.

Deduce whether this is confirmed by the experimental data.

distance between top plate and bottom plate = 1.55 cm

The student determined the terminal velocity of the oil drop in order to obtain a value for the weight of the oil drop.

He disconnected the power supply and the oil drop fell downwards. He viewed the oil drop through a microscope.

Explain why the student should wait a short while before starting to take measurements.

The view through the microscope is shown below. The scale is in millimetres.

The position of the oil drop at the start and end of a 120 s time interval is indicated by the black dots.

Determine the terminal velocity of the oil drop.

The student repeated the measurements on fifty oil drops. For each drop the student calculated the charge on the oil drop.

His results are shown in the bar chart.

The student predicted that the charge on each oil drop would be a whole number multiple of the charge on an electron.

Comment on the extent to which the bar chart supports the student’s prediction.

The student displaced the pendulum through a small angle so that it oscillated. She determined the time period T as 2.50 s.

Calculate the length of the pendulum.

Explain why the amplitude of oscillation of the pendulum did not stay constant.

The student recorded how the amplitude of oscillation varied over time.

It is suggested that the relationship between amplitude A and time t is

where A₀ is the initial amplitude of the oscillation and k is a constant. Explain why a graph of lnA against t would give a straight line.

The table shows the student’s data.

Plot a graph of lnA against t on the grid opposite. Use the additional column to show your processed data.

Determine values for A₀ and k.

The photograph shows some metal washers. A student carried out an experiment to determine the density of the metal the washers are made from.

Each washer has a diameter d₁ of about 4.5 cm. The internal diameter d₂ of each washer is about 2.5 cm. Each washer has a thickness t of about 4 mm.

The student used a half metre rule to make measurements of a washer.

Comment on the student’s choice of measuring instrument.

The student measured t for each of the five washers and then calculated a mean value.

Explain how the student could modify her method to obtain a more accurate mean value for t.

Show that the percentage uncertainty in her value for the area of a washer is about 3%.

The student obtained the following values of t for each of the five washers.

The table shows the density of iron and steel.

Deduce whether the washers are made from iron or steel.

mean mass of a washer = 32.0 g

The uncertainty in the mass is negligible.