Physics 3

X rays:

• found on electromagnetic spectrum
• absorbed by dense material such as bone and material, but pass through less dense material
• used in industry, labs and medicine  
• X rays ionise cells and repeated exsposure can cause cancer, people who work with x rays are protected behind lead screens 

Ultrasound:

• frequency above 20,000Hz 
• ultrasound can be used to measure the distance between materials; speed of different…