Ultrasound (Edexcel GCSE Physics Combined Science): Flashcards
📚Flashcards
Practise the cards
14 cards from this deck
ShowHide
Practise the cards
14 cards from this deck
What frequency is ultrasound?
What frequency is ultrasound?
Above 20,000 Hz (20 kHz)
Can humans hear ultrasound?
Can humans hear ultrasound?
No, frequency is too high
What do devices generate to create ultrasound?
What do devices generate to create ultrasound?
Electrical oscillations at any frequency
How are electrical oscillations converted to ultrasound?
How are electrical oscillations converted to ultrasound?
Converted to mechanical vibrations
What is partial reflection in ultrasound?
What is partial reflection in ultrasound?
Part of wave reflects at boundary, rest transmits
What happens to transmitted ultrasound?
What happens to transmitted ultrasound?
Continues through and may be refracted
Why is partial reflection useful?
Why is partial reflection useful?
Detects boundaries between substances
How is boundary distance calculated?
How is boundary distance calculated?
Using time for echoes to return to detector
Medical ultrasound imaging example
Medical ultrasound imaging example
Prenatal scanning of foetus
What causes reflections in prenatal scans?
What causes reflections in prenatal scans?
Boundaries between media (e.g. fluid/skin)
How is foetal image created?
How is foetal image created?
Computer processes timing & distribution of echoes
Industrial ultrasound imaging use
Industrial ultrasound imaging use
Finding flaws in materials (metal/wood)
Where does ultrasound normally reflect in materials?
Where does ultrasound normally reflect in materials?
From far side of material
How does ultrasound indicate material flaw?
How does ultrasound indicate material flaw?
Waves reflected sooner than expected