10 What actually comes up

Three years of real questions, part by part, with the grade band each part sat at according to that year's marking schedule. Start with the pattern table — it is the fastest way to decide what to revise.

Across 3 years

9 questions · 38 parts 10 Achieved 28 Merit 18 Excellence

The pattern — what to prepare

Topic	Appears in	Grade level	What to practise
Doppler: a moving source, explained and calculated	Every year	Achieved–Excellence	Which sign in the formula; always say the speed of sound is unchanged (a mark every year). Two frequencies heard, coming and going: two equations, never the midpoint.
Doppler off the line of travel: frequency–position graphs	2024, 2025	Merit–Excellence	Only the velocity towards the listener counts: the actual frequency at closest approach. A rise on the way in, or a fall that carries on long after it passes, means the source is speeding up.
Standing waves: drawing a harmonic with N and A labelled	Every year	Achieved–Merit	Pipe open/closed versus string; node at the closed end; loops even, ending on the right kind of point.
Standing wave / pipe frequency calculations	Every year	Achieved–Excellence	λ for the harmonic, then v = fλ; closed pipes only give odd harmonics; convert cm to m.
How standing waves form; why a closed pipe skips even harmonics	2024	Merit–Excellence	A wave and its reflection superpose; node at the closed end, antinode at the open end; only odd quarter-wavelengths fit.
What tension and length do to a string’s note	2023, 2025	Achieved–Merit	Length sets λ, tension sets v (v = √(T/μ)), and f = v/λ follows.
Beats (forming, and listening as a frequency changes)	Every year	Merit–Excellence	\|f₁ − f₂\|; in and out of phase over time, never path difference; the beats slow and vanish as the two frequencies approach.
Resonance (driving at the natural frequency), and stopping it	2023	Achieved–Excellence	Driving frequency matches the natural frequency, so amplitude builds; stop it by changing a frequency or adding damping.
Double-slit and diffraction-grating interference	Every year	Achieved–Excellence	nλ is the path difference; nλ = d sinθ and the small-angle nλ = dx/L, but find θ from tan θ = x/L when the angle is big (2023, 2025).
Comparing a grating with a double slit	2024, 2025	Merit–Excellence	Brighter, sharper, further apart (or the reverse) — justify each difference.
White light through a grating — colour order	2023, 2024	Merit	Violet needs the smallest path difference, so the smallest angle: violet on the inside. Never “red diffracts more”.
Diffraction definition & the dark regions between maxima	2023	Achieved–Excellence	Spreading through a gap lets the slits’ light overlap; many slits cancel everywhere except the bright directions.

not tried got it to review 2025 three questions 13 parts

The 2025 paper ↗ Marking schedule ↗

Question 1 — Doppler effect

Martyn and Kerryn are riding jet skis on a lake. Martyn's jet ski has an air horn that emits 1043 Hz. Kerryn stops, and Martyn travels directly towards her at 27.3 m s⁻¹. The speed of sound in air is 343 m s⁻¹.

f source = 1043 Hz
v source = 27.3 m s⁻¹
v sound (air) = 343 m s⁻¹

Not tried yet: a Calculate the frequency of the sound that Kerryn hears.Worked solution → Achieved
Not tried yet: b Explain why Kerryn hears a different frequency from the one the air horn emits.Worked solution → Merit
Not tried yet: c Kerryn floats very close to the jet ski's path, while her friend Erin watches from the bank. Both are level with point B, where the jet ski passes closest to them; Erin is further from the path. A graph on the paper shows the frequency each of them hears as the jet ski travels from A, through B, to C. Explain why the frequency Kerryn hears is the same as, or different from, the frequency Erin hears.Worked solution → Merit to Excellence
Not tried yet: d An underwater microphone monitors noise from jet ski engines. Martyn's engine makes a sound at 574.0 Hz. As the jet ski travels away from the microphone at 27.3 m s⁻¹, the microphone measures 563.6 Hz from the engine. Calculate the velocity of sound in water.Worked solution → Merit to Excellence

Question 2 — standing waves

A cello's strings are held at each end by the bridge and the nut, 0.690 m apart, and can vibrate in different harmonics.

L = 0.690 m

Not tried yet: a Draw a diagram of the 4th harmonic on the string, and label the nodes and antinodes.Worked solution → Achieved
Not tried yet: b After the cello has been in storage, the tension in its strings has decreased and it is out of tune: the strings play a frequency other than the desired one. The paper gives v = √(tension ÷ mass per unit length) for a wave on a string. No calculations are required. Use the equation to explain how this could make the frequency higher or lower than the desired frequency.Worked solution → Merit
Not tried yet: c When the 0.690 m string is played, its first harmonic is 147 Hz. A finger is then pressed onto the string, shortening it so that its first harmonic is 207 Hz. Assume the tension stays the same. Calculate the new length of the string when the 207 Hz note is played.Worked solution → Merit to Excellence
Not tried yet: d i Two neighbouring strings can be played together. Played with no finger on it, string 2 gives 98.0 Hz. Strings 1 and 2 are played at the same time while a finger presses on string 1, and string 1's length is gradually reduced until a beat is heard. Explain why beats form.Worked solution → Merit to Excellence
Not tried yet: d ii Explain what will be heard as the length of string 1 continues to be gradually reduced.Worked solution → Merit to Excellence

Question 3 — interference patterns

A laser shines green light onto a double slit of separation 1.25 × 10⁻⁴ m. Each slit acts as a light source in phase with the other, giving an interference pattern of closely spaced fringes on a screen. With the screen 3.40 m from the slits, the distance from the central maximum to the 3rd-order maximum is 4.20 × 10⁻² m.

d = 1.25×10⁻⁴ m
L = 3.40 m
x (centre to 3rd order) = 4.20×10⁻² m

Not tried yet: a Show that the laser has a wavelength of 515 nm.Worked solution → Achieved
Not tried yet: b The paper shows a photo of the pattern from the two slits: a row of bright green fringes with dark gaps between them. Explain why the intensity of the light on the screen varies like this.Worked solution → Merit
Not tried yet: c The double slit is replaced with a diffraction grating whose slits are more closely spaced. Describe and explain the changes to the interference pattern on the screen.Worked solution → Merit to Excellence
Not tried yet: d In another experiment, a green 515 nm laser is shone through a different diffraction grating and 7 maxima are seen on the screen. The screen is 0.900 m wide, centred on the straight-through beam, and 1.20 m from the grating. Calculate the possible range of values for the slit separation of the grating.
- λ = 515 nm
- screen width = 0.900 m
- grating to screen = 1.20 m
Worked solution → Merit to Excellence

2024 three questions 12 parts

The 2024 paper ↗ Marking schedule ↗

Question 1 — the pan flute

A pan flute is a set of pipes of different lengths bound together, each CLOSED at one end and open at the other. Sound is made by blowing across the open ends. Jane's shortest pipe is 8.50 cm long and her longest is 17.5 cm. The speed of sound in air is 343 m s⁻¹.

v sound = 343 m s⁻¹
shortest pipe = 8.50 cm
longest pipe = 17.5 cm

Not tried yet: a Draw the third harmonic that a pan flute pipe can produce, and label the nodes (N) and antinodes (A).Worked solution → Achieved
Not tried yet: b Calculate the frequency of the third harmonic produced in the shortest pipe.Worked solution → Merit
Not tried yet: c Explain how standing waves form in a pan flute pipe, open at one end and closed at the other, and explain why not all harmonics can form.Worked solution → Merit to Excellence
Not tried yet: d Some pan flutes are tuned by moving a small cork inside a pipe to change its length. At first the longest pipe is too long, and this untuned pipe makes a beat of 9.00 Hz with a tuned pipe. The tuned pipe is 0.164 m long and plays 523 Hz on its first harmonic. Calculate how much further the cork needs to be pushed into the pipe, and explain how you can hear when the cork is in the right position.Worked solution → Merit to Excellence

Question 2 — interference

Jane's physics teacher shines a red laser through a diffraction grating placed at the centre of a semicircular screen. The pattern on the screen is a number of narrow, bright fringes.

200 lines per mm
λ = 638 nm

Not tried yet: a The grating formula is nλ = d sinθ, where n is the order number and λ is the wavelength. What does the term nλ represent?Worked solution → Achieved
Not tried yet: b The grating has 200 lines per mm, and the laser's wavelength is 638 nm. Calculate the total number of dots seen on the semicircular screen, beginning with the distance between the slits.Worked solution → Merit to Excellence
Not tried yet: c The same red laser is shone through two slits that are the same width as the grating's slits, but further apart. Describe the differences between the two-slit pattern and the grating's pattern, and explain the reason for each difference.Worked solution → Merit to Excellence
Not tried yet: d White light is shone onto the grating. The pattern has a white central region, and the other orders form complete spectra on either side of it. Explain why white light forms spectra, with violet on the inside and red on the outside, when it passes through a diffraction grating.Worked solution → Merit

Question 3 — Doppler effect

Jane and her classmates stand on a railway platform, listening to a train approach them at a constant speed, blowing its whistle. The speed of sound in air is 343 m s⁻¹.

v sound = 343 m s⁻¹

Not tried yet: a Describe what Jane and her friends hear, compared with the driver, as the approaching train blows its whistle.Worked solution → Achieved
Not tried yet: b Explain why Jane and her friends hear a change in frequency as the approaching train blows its whistle.Worked solution → Merit
Not tried yet: c They hear 1270 Hz as the train approaches, and 1190 Hz after it has passed them and is moving away at the same constant speed. Calculate the speed of the train.Worked solution → Merit to Excellence
Not tried yet: d Another train approaches and goes past them without stopping. A graph on the paper shows the frequency they hear against the train's position, marked Section A (approaching), Point B (right in front of them) and Section C (going away), with a line at the whistle's actual frequency. Using the shape of the graph, explain what may be happening (i) as the train approaches (Section A), (ii) as it is right in front of them (Point B), and (iii) as it goes away (Section C).Worked solution → Merit to Excellence

2023 three questions 13 parts

The 2023 paper ↗ Marking schedule ↗

Question 1 — Sam's violin

A violin's strings are fixed at both ends, 0.331 m apart, and Sam makes them vibrate with a bow. One string, the "G", plays a fundamental frequency of 196 Hz. Assume the speed of sound in air is 342 m s⁻¹.

L = 0.331 m
f₁ = 196 Hz
v sound = 342 m s⁻¹

Not tried yet: a Calculate the speed of the wave that travels along the string.Worked solution → Achieved
Not tried yet: b The vibrating string is found to vibrate at 392 Hz and 588 Hz as well. State the harmonic that causes the vibration at 588 Hz. Include a sketch showing where the nodes and antinodes are.Worked solution → Merit
Not tried yet: c Sam plays the violin (fundamental 196 Hz) sitting on a trailer that moves at 5.30 m s⁻¹ directly towards microphone A. Calculate the frequency recorded by microphone A.Worked solution → Merit
Not tried yet: d Microphone A is directly in front of the moving trailer, and microphone B directly behind it. Explain how the trailer's motion, with Sam on it playing, affects: the frequency of the string; the speed of the sound in the air; the wavelength of the sound in front of and behind the violin; and the frequencies detected by microphones A and B.Worked solution → Merit to Excellence

Question 2 — violin tuning

On a hot day the violin goes out of tune easily, and Sam has to adjust the tension in the "G" string to keep it vibrating at 196 Hz.

Not tried yet: a Describe what happens to the fundamental frequency of the string when the string gets longer, with nothing else changing.Worked solution → Achieved
Not tried yet: b Sam plays the string while sounding a tuning fork that always vibrates at 196 Hz, and hears a beat. Describe what is meant by a beat, and explain why beats are heard.Worked solution → Merit
Not tried yet: c Sam hears a beat of 2.1 Hz. She then increases the speed of the wave along the string by tightening it, and the beat frequency increases. (i) Determine the possible frequencies of the string. (ii) Use the tightening to decide which frequency it was vibrating at before adjustment. (iii) Explain what Sam must do to get the string to 196 Hz. (iv) State how she will know when it is vibrating at 196 Hz.Worked solution → Merit to Excellence
Not tried yet: d i When Sam plays a frequency of 564 Hz near a wine glass, the glass rattles on the shelf. Describe this phenomenon, as part of an in-depth explanation of it.Worked solution → Merit to Excellence
Not tried yet: d ii Explain how she might stop the wine glass from vibrating when she plays the violin.Worked solution → Achieved

Question 3 — diffraction glasses

At a fair, children buy “Rainbow Glasses” made of diffraction gratings in a cardboard frame. Steve shines a laser pointer of wavelength 643 nm (6.43 × 10⁻⁷ m) through one of the gratings onto a wall. The pattern is a bright red spot at the centre, with slightly dimmer red spots either side. The wall is 1.43 m from the grating, and the distance from the central bright spot to the second dimmer spot is 1.75 m.

λ = 643 nm (6.43 × 10⁻⁷ m)
grating to wall = 1.43 m
centre to 2nd spot = 1.75 m

Not tried yet: a Describe diffraction.Worked solution → Achieved
Not tried yet: b Give an in-depth explanation of why this pattern is seen: explain how diffraction and interference cause the bright spots, and why there are large sections with no light between them.Worked solution → Merit to Excellence
Not tried yet: c Calculate the slit separation in the grating.Worked solution → Merit to Excellence
Not tried yet: d Looking at a spot of white light through the glasses, the children see the white spot with spectra on either side (“rainbows”). Give an in-depth explanation: describe where the spectra occur, explain the position of the colours in them and why they are there, and include a labelled sketch.Worked solution → Merit

Read the last column as a to-do list. Doppler, standing waves, beats and interference come up every year. Every (a) in the last three papers was Achieved, and no part was Excellence alone: each one that reaches Excellence starts at Merit.

Practice for this standard covers the whole topic — flashcards and quiz.