Question Constellation Sign up for free AQA · GCSE · Physics · Higher
Electromagnetic Wave Transmission and Detection
A person is using a mobile phone to allow a laptop to access the Internet.
The electromagnetic waves emitted by the mobile phone send information to the laptop.
The electromagnetic waves are produced by oscillations in the transmitter of the mobile phone.
Explain how oscillations in the transmitter enable information to be transferred to the detector in the laptop.
Write your answer first. You can study the marking guidance whenever you need it.
Study the marking See what earns credit and compare it with a full-mark answer.
Marking points
- 1 States that the transmitter produces radio waves or microwaves.
- 2 States that the laptop detector absorbs the waves or their energy.
- 3 Explains that absorption produces an alternating current or causes electrons to oscillate.
- 4 Links the detector current/oscillation frequency to the transmitted waves or transmitter oscillations.
Full-mark answer
Oscillations in the phone's transmitter produce radio waves (or microwaves). The detector in the laptop absorbs the waves and their energy, producing an alternating current, or making electrons oscillate, at the same frequency as the transmitted waves.
Why this answer loses marks
The phone sends a signal that the laptop receives.
This restates the setup but omits the credited mechanism: production of radio/microwaves, absorption at the detector, induced alternating current/electron oscillation, and matching frequency.