Ultrasound is used to scan unborn babies but X-rays are not used to scan unborn babies.
Ultrasound is not ionising as it is a longitudinal wave whilst X-rays are ionising as they are transverse waves and have very high frequency hence can 'knock' electrons out of their orbit. Doing this can cause mutations in the cells of the baby and potentially cause cancer.
SA
Related Physics GCSE answers
All answers ▸What are the definitions of a)voltage and b)current?
What is terminal velocity?
A car travels 100 metres in 20 seconds. i) What is the cars speed? ii) How far would the car travel in 1 minute 40 seconds?
Describe the forces acting on a skydiver jumping out of a plane and explain why opening a parachute reduces the velocity