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A car aerial receives radio waves from a radio transmitter - AQA - GCSE Physics Combined Science - Question 5 - 2018 - Paper 2
Question 5
A car aerial receives radio waves from a radio transmitter. Radio waves are transverse waves. Sound waves are longitudinal waves. 1. Describe the difference between... show full transcript
Worked Solution & Example Answer:A car aerial receives radio waves from a radio transmitter - AQA - GCSE Physics Combined Science - Question 5 - 2018 - Paper 2
Step 1
Describe the difference between transverse waves and longitudinal waves.
Answer
In a longitudinal wave, the oscillations occur parallel to the direction of energy transfer. An example of this would be sound waves, which compress and expand in the medium. In contrast, in a transverse wave, the oscillations are perpendicular to the direction of energy transfer. This is exemplified by water waves, where the wave moves horizontally while the water particles move up and down.
Step 2
Calculate the wavelength of the radio waves.
Answer
To calculate the wavelength, use the formula:
ext{Wavelength} = rac{ ext{Wave speed}}{ ext{Frequency}}
Given:
- Wave speed =
- Frequency =
Substituting these values into the formula:
Thus, the wavelength of the radio waves is approximately m when rounded to 2 significant figures.
Step 3
Describe how the radio waves reaching the car aerial produce signals in the electrical circuit of the car radio.
Answer
The car aerial absorbs radio waves or energy. As the radio waves interact with the aerial, they cause electrons in the aerial to vibrate. This vibration creates an alternating current in the aerial circuit. The frequency of this alternating current corresponds to the frequency of the incoming radio waves, allowing the radio to decode the signal and produce sound.