Physics: Standard Level
Wave behaviour — Theme C
- 1.
A wave has frequency 500 Hz and travels at 340 m/s through air. Calculate its wavelength.
[3 marks] - 2.
Marking analysis: A learner attempts the following task: “A wave has frequency 500 Hz and travels at 340 m/s through air. Calculate its wavelength.” Their response addresses only this point: “Uses v = fλ.” Evaluate the response against the complete 3-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[3 marks] - 3.
Distinguish between a transverse wave and a longitudinal wave, giving one example of each.
[2 marks] · no calculator - 4.
Marking analysis: A learner attempts the following task: “Distinguish between a transverse wave and a longitudinal wave, giving one example of each.” Their response addresses only this point: “States that in a transverse wave, the oscillation is perpendicular to the direction of energy transfer, e.g. light or a water wave.” Evaluate the response against the complete 2-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[2 marks] · no calculator - 5.
Explain the phenomenon of diffraction, and state how the amount of diffraction depends on the relationship between wavelength and gap size.
[3 marks] · no calculator - 6.
Marking analysis: A learner attempts the following task: “Explain the phenomenon of diffraction, and state how the amount of diffraction depends on the relationship between wavelength and gap size.” Their response addresses only this point: “States that diffraction is the spreading of a wave as it passes through a gap or around an obstacle.” Evaluate the response against the complete 3-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[3 marks] · no calculator - 7.
Two coherent wave sources produce an interference pattern. State the condition for constructive interference and the condition for destructive interference, in terms of path difference.
[3 marks] · no calculator - 8.
Marking analysis: A learner attempts the following task: “Two coherent wave sources produce an interference pattern. State the condition for constructive interference and the condition for destructive interference, in terms of path difference.” Their response addresses only this point: “States that constructive interference occurs when the path difference is a whole number of wavelengths (nλ, n = 0, 1, 2...).” Evaluate the response against the complete 3-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[3 marks] · no calculator - 9.
A string fixed at both ends of length 0.80 m vibrates in its fundamental (first harmonic) standing wave mode. Calculate the wavelength of this standing wave.
[3 marks] - 10.
Marking analysis: A learner attempts the following task: “A string fixed at both ends of length 0.80 m vibrates in its fundamental (first harmonic) standing wave mode. Calculate the wavelength of this standing wave.” Their response addresses only this point: “States that the fundamental mode of a string fixed at both ends has a node at each end and one antinode in the middle, so the string length equals half a wavelength.” Evaluate the response against the complete 3-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[3 marks] - 11.
Distinguish between a standing (stationary) wave and a travelling wave, in terms of energy transfer.
[2 marks] · no calculator - 12.
Marking analysis: A learner attempts the following task: “Distinguish between a standing (stationary) wave and a travelling wave, in terms of energy transfer.” Their response addresses only this point: “States that a travelling wave transfers energy from one place to another.” Evaluate the response against the complete 2-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[2 marks] · no calculator - 13.
A wave travels from deep water into shallow water and its speed decreases. Explain what happens to its wavelength, and state what happens to its frequency.
[3 marks] · no calculator - 14.
Marking analysis: A learner attempts the following task: “A wave travels from deep water into shallow water and its speed decreases. Explain what happens to its wavelength, and state what happens to its frequency.” Their response addresses only this point: “States that the frequency of the wave remains unchanged, since it is set by the source generating the wave.” Evaluate the response against the complete 3-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[3 marks] · no calculator - 15.
Describe an experiment using a ripple tank to demonstrate the reflection of a plane water wave from a straight barrier, and state the relationship between the angle of incidence and the angle of reflection.
[3 marks] · no calculator - 16.
Marking analysis: A learner attempts the following task: “Describe an experiment using a ripple tank to demonstrate the reflection of a plane water wave from a straight barrier, and state the relationship between the angle of incidence and the angle of reflection.” Their response addresses only this point: “Describes generating plane water waves in a ripple tank using a vibrating bar, directed at a straight barrier placed in the water.” Evaluate the response against the complete 3-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[3 marks] · no calculator - 17.
Light of wavelength 600 nm passes through a diffraction grating with 500 lines per mm. Calculate the angle of the first-order maximum, using nλ = d sinθ.
[4 marks] - 18.
Marking analysis: A learner attempts the following task: “Light of wavelength 600 nm passes through a diffraction grating with 500 lines per mm. Calculate the angle of the first-order maximum, using nλ = d sinθ.” Their response addresses only this point: “Calculates the grating spacing d = 1/(500 lines/mm) = 2.0 × 10⁻⁶ m.” Evaluate the response against the complete 4-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[4 marks] - 19.
A source of sound moves towards a stationary observer. Explain, using the Doppler effect, why the observer hears a higher frequency than the source emits.
[3 marks] · no calculator - 20.
Marking analysis: A learner attempts the following task: “A source of sound moves towards a stationary observer. Explain, using the Doppler effect, why the observer hears a higher frequency than the source emits.” Their response addresses only this point: “States that as the source moves towards the observer, successive wavefronts are emitted from positions closer to the observer than the previous one.” Evaluate the response against the complete 3-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[3 marks] · no calculator - 21.
In a double-slit experiment, light of wavelength 550 nm passes through two slits separated by 0.20 mm, producing an interference pattern on a screen 2.0 m away. Calculate the fringe spacing.
[4 marks] - 22.
Marking analysis: A learner attempts the following task: “In a double-slit experiment, light of wavelength 550 nm passes through two slits separated by 0.20 mm, producing an interference pattern on a screen 2.0 m away. Calculate the fringe spacing.” Their response addresses only this point: “States the fringe spacing formula: s = λD/d.” Evaluate the response against the complete 4-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[4 marks] - 23.
State what is meant by plane polarisation of a transverse wave, and explain why longitudinal waves, such as sound, cannot be polarised.
[3 marks] · no calculator - 24.
Marking analysis: A learner attempts the following task: “State what is meant by plane polarisation of a transverse wave, and explain why longitudinal waves, such as sound, cannot be polarised.” Their response addresses only this point: “States that a plane-polarised transverse wave oscillates in only one fixed plane (direction), rather than in all directions perpendicular to the direction of travel.” Evaluate the response against the complete 3-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[3 marks] · no calculator - 25.
A ray of light travels from air into a glass block, with an angle of incidence of 50° and an angle of refraction of 30°. Calculate the refractive index of the glass.
[3 marks] - 26.
Marking analysis: A learner attempts the following task: “A ray of light travels from air into a glass block, with an angle of incidence of 50° and an angle of refraction of 30°. Calculate the refractive index of the glass.” Their response addresses only this point: “Uses n = sin(angle of incidence)/sin(angle of refraction).” Evaluate the response against the complete 3-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[3 marks] - 27.
The refractive index of a certain glass is 1.55. Calculate the critical angle for light travelling from this glass into air.
[3 marks] - 28.
Marking analysis: A learner attempts the following task: “The refractive index of a certain glass is 1.55. Calculate the critical angle for light travelling from this glass into air.” Their response addresses only this point: “Uses sin(critical angle) = 1/n.” Evaluate the response against the complete 3-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[3 marks] - 29.
A car horn emits sound at a frequency of 500 Hz. The car moves towards a stationary observer at 30 m/s. Calculate the frequency heard by the observer, using f′ = fv/(v − vs), where v = 340 m/s is the speed of sound.
[4 marks] - 30.
Marking analysis: A learner attempts the following task: “A car horn emits sound at a frequency of 500 Hz. The car moves towards a stationary observer at 30 m/s. Calculate the frequency heard by the observer, using f′ = fv/(v − vs), where v = 340 m/s is the speed of sound.” Their response addresses only this point: “States f′ = fv/(v − vs), for a source moving towards a stationary observer.” Evaluate the response against the complete 4-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[4 marks] - 31.
An autonomous survey boat sends a short sound pulse vertically downward in freshwater. The echo returns 0.0720 s later. The speed of sound in the water is 1480 m s⁻¹ and the timing uncertainty is ±0.0010 s. (a) Calculate the water depth. (b) Determine the percentage uncertainty in the depth due to timing. (c) Explain why an echo is produced at the lake bed.
[4 marks] - 32.
Marking analysis: A learner attempts the following task: “An autonomous survey boat sends a short sound pulse vertically downward in freshwater. The echo returns 0.0720 s later. The speed of sound in the water is 1480 m s⁻¹ and the timing uncertainty is ±0.0010 s. (a) Calculate the water depth. (b) Determine the percentage uncertainty in the depth due to timing. (c) Explain why an echo is produced at the lake bed.” Their response addresses only this point: “Recognises the pulse travels twice the depth and uses d = vt/2.” Evaluate the response against the complete 4-mark task. Identify what earns credit and state every additional requirement needed for full marks.
[4 marks]