O-LevelPhysicsWaves5054/22 · Oct/Nov 2025 · Q58 Marks

The microwave region is one region of the electromagnetic spectrum.

(a)Fig. 5.1 represents the electromagnetic spectrum divided into the seven main regions. The regions are arranged from left to right in order of increasing wavelength. On Fig. 5.1: indicate the microwave region by marking it with the letter M; indicate the ultraviolet region by marking it with the letters UV.[1]
(b)(i)The frequency of the microwaves used by some satellite television systems is 12GHz. The speed of microwaves in a vacuum is 3.0 x 10⁸ m/s. Calculate the wavelength of these microwaves in a vacuum.[3]
(b)(ii)Describe how microwaves are used in satellite television systems.[2]
(c)All microwave ovens have a switch that turns the oven off when the door is opened. Suggest why it is important for a microwave oven to switch off when the door is opened.[2]

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2025). The mark or mark type is shown in brackets.

[1] (a) UV in 3rd box from left and M in 6th box from left correctly placed
[1] (b)(i) (λ =) c/f or 3.0 x 10^8 / 1.2 x 10^10
[1] (b)(i) 2.5 x 10^-2 (m) (C1 is for calculating the correct value from c/f, A1 for units and value correct)
[1] (b)(ii) encoded microwave/microwave signal/microwave carrying data/microwave transmitting data (to satellite from Earth)
[1] (b)(ii) satellite transmits microwave to Earth/dish/antenna/subscriber/television
[1] (c) to prevent microwaves escaping/leaving the oven/spreading out of the device
[1] (c) microwaves/they can cause burns (in living tissue/people)/damage to tissue through heating/blisters

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