6 factoids about X-rays

What are X-rays used for?
(4 egs)

Precautions to be taken when X-ray machines and CT scanners are in use.

Range of human hearing

What is ultrasound?

How are ultrasonic waves used to find cracks in materials?

Calculation of the distance between interfaces in various media.

Use of ultrasound in medicine

What is refraction?

What does a lens do to light to form an image?

What does a convex lens do to light?

What defines the 'nature' of an image?

The nature of the image produced by a converging lens for an object placed at different distances from the lens.

The nature of the image produced by a concave or diverging lens.