AQA GCSE Physics Physics Paper 2 (Foundation), June 2023: Question 6

✅ Correct Answer

Tick: It will be harder to judge where the centre of the beam is.

💡 Key Knowledge

When measuring angles of incidence and refraction, rays must be as thin as possible to pinpoint the exact centre of the beam relative to the normal line.

✅ Correct Answer

• Ray shown refracted to the right (bending towards the normal) as it enters the glass block.
• Ray refracted away from the normal as it exits the block back into the air.
• Emergent ray must be perfectly parallel to the original incident ray.

🧠 Exam Technique

Use a sharp pencil and a ruler. Remember that light slows down moving from air (less dense) into glass (more dense), bending towards the normal. When exiting back into the air, it speeds up and bends away from the normal by the exact same angle.

❌ Common Errors

Students often draw the light ray continuing straight through the block without changing direction, or they fail to make the emerging ray parallel to the incident ray.

✅ Correct Answer

Tick: 1 degree

💡 Key Knowledge

The resolution of a measuring instrument is the smallest change in the quantity being measured that causes a perceptible change in the reading. On a standard school protractor, the smallest scale division is 1 degree.

📐 Calculation Steps

1. Add the repeated measurements together: 35 + 31 + 33 = 99
2. Divide by the number of measurements (3): 99 / 3 = 33

Mean angle of refraction = 33°

❌ Common Errors

Do not include anomalous data points blindly. In this set, all three values are close, so none are discarded. Always check if a mean requires rounding to a sensible number of significant figures.

✅ Correct Answer

Missing word: absorbed (or filtered out / stopped )

💡 Key Knowledge

Colour filters work by transmission and absorption. A red filter transmits red light waves while absorbing all other wavelengths of light present in the white light spectrum.

✅ Correct Answer

wave speed = frequency × wavelength (or v = f × λ )

🧠 Exam Technique

Always memorize core equations from the physics equation sheet. You can write words or accepted standard symbols ( v , f , λ ).

📐 Step-by-Step Calculation

1. State the equation: v = f × λ
2. Substitute known values: 3.0 × 10⁸ = 4.0 × 10¹⁴ × λ
3. Rearrange for wavelength (λ): λ = (3.0 × 10⁸) / (4.0 × 10¹⁴)
4. Calculate final value: λ = 7.5 × 10⁻⁷ m (or 0.00000075 m )

Wavelength = 7.5 × 10⁻⁷ m

❌ Common Errors & Traps

• Forgetting to rearrange the equation properly before substituting numbers.
• Entering standard form numbers incorrectly into calculators (use the EXP or ×10ˣ button, not multiplication by 10 manually).
• Omitting standard units or writing incorrect powers of ten.