Intensity, refraction and total internal reflection: Edexcel International A Level Physics questions

Every Edexcel International A Level Physics exam question on Intensity, refraction and total internal reflection (specification points 44–48), 2019–2025, with its mark scheme and examiner’s report.

All 108 questions on Intensity, refraction and total internal reflection, as a list

June 2025, AS Unit 2, Q1 (1 mark): The refractive index of vegetable oil is 1.47 –1, in vegetable oil? Which of the following is the speed of light, in m s A 1.59 × 10 8 B 2.04 × 10 8 C 3.00 × 10
June 2025, AS Unit 2, Q2 (1 mark): A ray of light is incident on the boundary between Perspex and air, as shown. The angle of incidence i is greater than the critical angle for the Perspex-air bo
June 2025, AS Unit 2, Q12(a)(i) (1 mark): Determine the angle of incidence. (1) Angle of incidence =
June 2025, AS Unit 2, Q12(a)(ii) (2 marks): Calculate the angle of refraction in the glass block. refractive index of glass block = 1.5 (2) Angle of refraction =
June 2025, AS Unit 2, Q18(b)(i) (4 marks): Show that the total energy incident on the glass screen during this time is about 130 J. (4)
June 2025, AS Unit 2, Q18(d) (2 marks): Suggest why the hardening time of the glue is reduced if the UV lamp is moved closer to the mobile phone screen. (2)
January 2025, AS Unit 2, Q12 (3 marks): A solar cell of area 6.4 cm 2 is used to charge the battery in a watch. The battery will only charge when the power input to the solar cell is greater than 0.80
January 2025, AS Unit 2, Q18(a) (3 marks): The diagram shows a ray of light in air, incident on the end of this optical fibre. air glass Not to scale 50 Calculate the angle of refraction of the light as
January 2025, AS Unit 2, Q18(b) (3 marks): The diagram shows one ray of light inside the optical fibre, incident on a boundary with the air. air glass 45 Not to scale Deduce whether the ray will be total
January 2025, AS Unit 2, Q18(c) (5 marks): Data is transmitted along the optical fibre by pulses of light. One pulse of light initially has a constant intensity I for a duration T, as shown. Light intens
January 2025, AS Unit 2, Q18(d) (2 marks): Some optical fibres are surrounded by a thin layer of transparent material called cladding, as shown. cladding glass cladding The transparent material has a low
January 2025, AS Unit 3, Q3(a)(i) (1 mark): Suggest what the student should do to control the background light during the investigation. (1)
January 2025, AS Unit 3, Q3(a)(ii) (2 marks): Suggest two other variables the student should control during this investigation. (2)
January 2025, AS Unit 3, Q3(d)(i) (1 mark): State the direction in which light should be incident on the solar panel for maximum output power. (1)
January 2025, AS Unit 3, Q3(d)(ii) (3 marks): The solar panels at a solar power station are mounted on motorised stands. (Source: © Daryna Andriianova/Shutterstock) Explain how this could increase the energ
October 2024, AS Unit 2, Q1 (1 mark): Which of the following describes light intensity? A The energy of light incident on a surface per unit area B The power of light incident on a surface per unit
October 2024, AS Unit 2, Q17(a) (2 marks): Calculate the speed of light in water. (2) Speed of light in water =
October 2024, AS Unit 2, Q17(b) (6 marks): A person is swimming underwater in a lake. The person looks up towards the surface. Three rays of light, A, B and C, are incident on the surface of the water, a
October 2024, AS Unit 3, Q3(a) (3 marks): The student filled the tall beaker with water. He used a metre rule to measure the depth h1 of the water. Describe an accurate method to determine a single valu
October 2024, AS Unit 3, Q3(b) (3 marks): The student placed a steel nail at the bottom of the beaker. He viewed the search pin and the image of the steel nail from above while adjusting the height of t
October 2024, AS Unit 3, Q3(c)(i) (2 marks): Determine the mean value of n. (2) Mean value of n =
June 2024, AS Unit 2, Q3 (1 mark): The diagram shows a ray of light incident at a boundary between oil and water. The refractive index of water is 1.33 15 Not to scale oil water 17 Which of the f
June 2024, AS Unit 2, Q18(a) (2 marks): Explain why the ray of light refracts at surface X, as shown. (2)
June 2024, AS Unit 2, Q18(b) (4 marks): At surface Y the ray of light must be reflected. This reflection could be due to total internal reflection. If the ray of light is not totally internally reflec
June 2024, AS Unit 2, Q18(c)(i) (2 marks): The sensor has a known surface area. Explain why knowing the number of photons arriving each second at the sensor can not be used to determine the intensity of
January 2024, AS Unit 2, Q1 (1 mark): A ray of light in air is incident on a glass surface. The angle of incidence is less than the critical angle. Which of the following describes what happens to t
January 2024, AS Unit 2, Q8 (1 mark): At a distance d from a point source of light, the light intensity is I. Which of the following expressions gives the light intensity at a distance 2d from the s
January 2024, AS Unit 2, Q13(a) (2 marks): The refractive index of the hydro‑beads is very similar to the refractive index of water. Explain why the hydro‑beads are difficult to see when surrounded by wa
January 2024, AS Unit 2, Q13(b)(i) (2 marks): Calculate the angle of refraction r. (2) r =
January 2024, AS Unit 2, Q13(b)(ii) (3 marks): Complete the diagram to show what happens to the ray at position X. Your answer should include a calculation. (3)
January 2024, Unit 6, Q4(c)(i) (2 marks): Determine the value of n. (2) n =
January 2024, Unit 6, Q4(c)(iii) (2 marks): The refractive index of crown glass is 1.52 Deduce whether the lens could be made of crown glass. (2)
October 2023, AS Unit 2, Q16(c) (4 marks): A solar cell array is placed on the roof of a house as shown. The area of the solar cell array is 8.7 m 2. The roof of the house slopes at an angle of 60° to th
October 2023, AS Unit 2, Q18(a) (4 marks): Explain why the ray of light does not change direction when entering the glass block. Your answer should refer to wavefronts. (4)
October 2023, AS Unit 2, Q18(b) (3 marks): Show that the critical angle between glass and water is about 60°. refractive index of glass = 1.51 refractive index of water = 1.33 (3)
October 2023, AS Unit 2, Q18(c) (3 marks): Complete the diagram to show the path of the ray of light after meeting the boundary between the glass and water. (3) layer of water laser pointer glass block
October 2023, AS Unit 2, Q18(d) (4 marks): The photograph shows a hand holding a glass beaker containing water. Fingerprints are a series of ridges and valleys on the surface of fingers. The valleys trap
June 2023, AS Unit 2, Q3 (1 mark): Monochromatic light is incident on a rectangular glass block. Some of the light is reflected and some of the light is refracted, as shown. incident light reflec
June 2023, AS Unit 2, Q9 (1 mark): Earth and Jupiter orbit the Sun, as shown. The distance from Earth to the Sun is 1.49 × 10 11 m. The distance from Jupiter to the Sun is 7.78 × 10 11 m. 11 m 7.
June 2023, AS Unit 2, Q13(a) (3 marks): Determine the refractive index of the water. You should take measurements from the diagram. (3) Refractive index =
June 2023, AS Unit 3, Q2(a)(i) (2 marks): Explain the purpose of the convex lens. (2)
June 2023, AS Unit 3, Q2(a)(ii) (2 marks): The power supply provided a constant 12 V potential difference across the filament bulb. Describe two more ways to keep the light intensity incident on the sola
January 2023, AS Unit 2, Q2 (1 mark): Monochromatic light travels through air and enters a glass block. Which of the following quantities does not change as light enters the glass block? A amplitude
January 2023, AS Unit 2, Q3 (1 mark): A ray of light approaches a boundary between air and glass, as shown. The angle of incidence is i. glass i air Which of the following statements about total int
January 2023, AS Unit 2, Q12(a)(i) (3 marks): Determine the refractive index of the glass. (3) Refractive index of glass =
January 2023, AS Unit 2, Q12(a)(ii) (1 mark): Draw, on the diagram, the ray of light as it emerges from the prism at A. No further calculations are required. (1)
January 2023, AS Unit 2, Q12(b) (2 marks): A different prism is made of glass with a refractive index of 1.63 Calculate the speed of light in this glass. (2) Speed of light in glass =
January 2023, AS Unit 2, Q16(a)(i) (4 marks): Calculate the minimum efficiency of the panel of solar cells that will operate the pump. intensity of sunlight on solar cells = 1040 W m –2 (4) Minimum efficien
January 2023, AS Unit 2, Q16(a)(ii) (2 marks): Suggest two reasons why the value calculated in (i) is the minimum efficiency that will operate the pump. (2)
October 2022, AS Unit 2, Q16(a)(i) (3 marks): Show that the critical angle for light incident on the boundary between the core and cladding is about 75°. (3)
October 2022, AS Unit 2, Q16(a)(ii) (3 marks): Explain what will happen to the ray of light after it meets the boundary between the core and cladding. The diagram is drawn to scale and you should use a measu
October 2022, AS Unit 2, Q16(b)(i) (3 marks): Calculate the time taken for light to travel in a straight line along 70.0 km of this optical fibre. (3) Time taken =
October 2022, AS Unit 2, Q16(b)(ii) (2 marks): Light may escape from the core into the cladding when the optical fibre is curved. A student suggests that using cladding with a lower refractive index would le
October 2022, AS Unit 2, Q17(c) (3 marks): The maximum intensity of sunlight at the Earth’s surface is about 1100 W m–2 . A student suggests that the intensity of light at a distance of 5.0 mm from an LE
October 2022, AS Unit 3, Q3(a)(i) (3 marks): Describe a method to measure u and v. (3)
October 2022, AS Unit 3, Q3(b)(i) (2 marks): For a lens, P can be calculated using P = 1 u + 1 v Calculate the value missing from the table. (2) P = D
October 2022, AS Unit 3, Q3(b)(ii) (3 marks): When surrounded by air, the power of a lens this shape can be calculated using the equation n − n   1 P = lens air  n r air where r is the radius of the c
June 2022, AS Unit 2, Q1 (1 mark): A ray of light is incident on the boundary between two materials, x and y, as shown. The refractive index value for material x is nx and for material y is ny. i
June 2022, AS Unit 2, Q3 (1 mark): When the distance between the Sun and the planet Mercury is 4.60 × 1010 m, the intensity of solar radiation at the surface of Mercury is 1.45 × 104 W m–2. Which
June 2022, AS Unit 2, Q11(a) (5 marks): Complete the diagram to show the path of the ray as it enters the block. Use the space below for any calculations. refractive index of glass = 1.58 (5)
June 2022, AS Unit 2, Q11(b) (3 marks): The speed of light in a different type of glass is 1.96 × 108 m s–1. Calculate the value of the critical angle at a boundary between this type of glass and air.
June 2022, AS Unit 3, Q2(a) (3 marks): When the measured value of θ1 is 35°, the measured value of θ2 is 62°. Calculate the percentage uncertainty in each of these values. (3) Percentage uncertainty
June 2022, AS Unit 3, Q2(b)(i) (3 marks): Explain why the gradient of this graph can be used to determine the refractive index of the transparent material. (3)
June 2022, AS Unit 3, Q2(b)(ii) (2 marks): Determine the refractive index of the transparent material. (2) Refractive index =
June 2022, AS Unit 3, Q3(c) (2 marks): Sketch the relationship between I and d on the axes below. (2) I d
June 2022, AS Unit 3, Q3(d) (3 marks): The student calculated the intensity of light incident on the LDR at each value of d. The output power of the filament lamp was 9.0 W. Calculate the intensity o
January 2022, AS Unit 2, Q5 (1 mark): Which of the following shows the relationship between vL, vM and vN? A vL > vM > vN B vL > vN > vM C vN > vM > vL D vM > vN > vL
January 2022, AS Unit 2, Q6 (1 mark): Which of the following could result in a ray of light undergoing total internal reflection? A light travelling from L to M B light travelling from L to N C ligh
January 2022, AS Unit 2, Q16(b)(i) (1 mark): State why the incident ray of light does not change direction as it enters prism A. (1)
January 2022, AS Unit 2, Q16(b)(ii) (4 marks): The refractive index of the glass in prism B is greater than the refractive index of the glass in prism A. When the ray of light reaches the boundary between th
January 2022, AS Unit 2, Q16(b)(iii) (3 marks): Calculate the angle of refraction as this ray of light travels across the boundary between prism A and prism B. refractive index of glass in prism A = 1.40 refr
January 2022, AS Unit 2, Q18(b) (4 marks): A light year is the distance travelled by light in one year. Sirius A is 8.60 light years from Earth. The intensity of radiation from Sirius A received on Earth
October 2021, AS Unit 2, Q11(a) (3 marks): In order to identify the material used, a ray of light is directed towards a boundary between air and the gemstone. 50° air gemstone 21° Deduce the material use
October 2021, AS Unit 2, Q11(b)(i) (4 marks): Add to the diagram to show the path of the ray of light as it leaves this boundary. Your answer should include a calculation. (4)
October 2021, AS Unit 2, Q11(b)(ii) (2 marks): Explain what would happen to the ray at this boundary if the material used was silicon carbide instead of diamond. (2)
October 2021, AS Unit 2, Q18(a) (3 marks): Calculate the intensity of solar radiation as it reaches ICESat-2. distance from the Sun to ICESat-2 = 1.50 × 1011 m power of the Sun = 3.83 × 1026 W (3) Intens
June 2021, AS Unit 2, Q3 (1 mark): A light bulb with an efficiency of 12% is positioned 2.0 m above a light sensor. The intensity of light at the light sensor is 0.14 W m−2. Which of the followin
June 2021, AS Unit 2, Q13(a) (5 marks): A ray of white light is incident on side AB of a rectangular glass block, as shown. 54.00° air A B 6.400 cm glass C D The red light and violet light from the in
June 2021, AS Unit 2, Q13(b) (4 marks): White light is incident on a boundary between glass and air, as shown. air glass 41.00° Explain what happens to the red light and the violet light when meeting
June 2021, Unit 6, Q4(c)(i) (2 marks): Determine the value of n. d = 5.10 cm ± 0.01 cm t = 8.30 mm ± 0.01 mm f = 9.8 cm ± 0.3 cm (2) n =
June 2021, Unit 6, Q4(c)(iv) (3 marks): The table shows data for some materials used to make lenses. Material Pyrex Crown glass Flint glass Refractive index 1.47 1.52 1.66 Deduce whether this lens cou
January 2021, AS Unit 2, Q8 (1 mark): A ray of light travels through glass, towards a boundary between glass and air. The critical angle for this boundary is 42°. Which row of the table is correct?
January 2021, AS Unit 2, Q15(a) (2 marks): Explain what is meant by refraction. (2)
January 2021, AS Unit 2, Q15(b) (3 marks): The simplified diagram below shows how a ray of light travels from the edge of the coin to the teacher’s eye, when the cup is partially filled with water. Diagr
January 2021, AS Unit 2, Q20(a) (3 marks): A typical smart meter emits radio waves with a power output of 1.00W. An intensity of radiation greater than 4.5 W m−2 is dangerous to people. A person stands 2
January 2021, AS Unit 3, Q2(a)(i) (1 mark): Complete the diagram to show the critical angle. (1)
January 2021, AS Unit 3, Q2(a)(ii) (2 marks): Determine the refractive index of the transparent material, using measurements from the diagram. (2) Refractive index =
January 2021, AS Unit 3, Q2(b) (2 marks): The student repeated the process for a second semicircular block of a different transparent material. Her measured value for C was 41 ± 0.5° Calculate the range
January 2021, AS Unit 3, Q2(c) (3 marks): The student had a rectangular block of transparent material. She made measurements as shown. transparent material incident ray 64° 36° Deduce whether this block
January 2021, AS Unit 3, Q2(d) (3 marks): The student used rays of white light. Explain why using monochromatic light would increase the validity of the conclusion made in (c). (3)
January 2021, AS Unit 3, Q2(e) (3 marks): The photograph shows a spectrometer. This can be used to measure angles when investigating refraction. collimator transparent material telescope Vernier scale L
October 2020, AS Unit 2, Q11(a) (2 marks): Calculate the angle of refraction within the glass block when θ = 43.0°. (2) Angle of refraction =
October 2020, AS Unit 2, Q11(b) (2 marks): Determine the critical angle for light at a glass-water boundary. (2) Critical angle =
October 2020, AS Unit 2, Q16(a) (5 marks): Explain why the sound follows the path shown in diagram B. Your answer should refer to refraction and diagram A. (5)
October 2020, AS Unit 2, Q16(b) (2 marks): Sound that travels in a straight line from the source to point P takes longer to arrive than sound that travels along the path shown in diagram B. Suggest why.
January 2020, AS Unit 2, Q12(a)(i) (2 marks): Calculate the maximum energy received by the solar panels in one hour. maximum intensity of solar radiation at the Earth’s surface = 1100 Wm–2 area of Sahara De
January 2020, AS Unit 2, Q12(a)(ii) (2 marks): Determine whether covering the Sahara Desert with solar panels would be able to generate enough electricity for the whole world. (2)
January 2020, AS Unit 2, Q12(b) (2 marks): Sand storms are common in the Sahara Desert. Explain why sand storms reduce the power generated by the solar panels. (2)
January 2020, AS Unit 2, Q15(a) (2 marks): Explain why the wave is refracted as shown, as it travels from deep water into shallow water. You may add to the diagram. (2)
January 2020, AS Unit 2, Q15(b)(i) (5 marks): Calculate the angle of refraction r. wavelength of waves in deep water = 15 m depth of deep water = 10 m depth of shallow water = 0.50 m angle of incidence = 40
January 2020, AS Unit 3, Q3(b) (2 marks): The student increased the density of the salt solution by adding different masses of salt. Sketch, on the axes below, a graph to show how the refractive index o
January 2020, AS Unit 3, Q3(c) (4 marks): The relationship between the refractive index n, the angle of incidence θ1 and the angle of refraction θ2 is given by the equation sin θ1 = n sin θ2 Describe a
January 2020, AS Unit 3, Q3(d)(i) (3 marks): The uncertainty in the measurement of the angles was ± 0.5°. Calculate the maximum and minimum values of n. (3) Maximum value of n = Minimum value of n =
June 2019, AS Unit 2, Q13(a) (3 marks): Calculate the minimum distance between the Earth and the Sun. power of the Sun 3.83 × 1026 W (3) Minimum distance =
June 2019, AS Unit 2, Q13(b) (3 marks): As Mars orbits the Sun, the intensity of radiation received at the top of its atmosphere varies from 491 W mí to 711 W mí. Explain two differences between the
June 2019, AS Unit 2, Q18(a) (2 marks): State the conditions required for total internal reflection to occur. (2)
June 2019, AS Unit 2, Q18(b) (2 marks): A ray of light is incident on the end of a glass fibre and refracts as it enters the glass. Explain why the light refracts as it enters the glass. (2)
June 2019, AS Unit 2, Q18(c) (4 marks): The diagram shows a ray of light being totally internally reflected at one side of a glass fibre and then refracting as it leaves the end of the fibre. The angl

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