Chapter 7: Rays and Waves

Transfers energy

________ when materials absorb light.

current oscillate

Can be produced artificially by making a(n) ________ in a transmitting aerial.

right angles

A line joining equivalent points on the object and image passes through the mirror at ________.

shorter wavelengths

As an object heats up, it radiates more ans more infrared, and ________.

Suns ultraviolet radiation is harmful to living cells

can cause skin cancer

Ultraviolet rays are harmful to living cells

commonly used to sterilize medical equipments

In engineering or in medical

they are used to detect flaws inside the material or a damaged bone

What is a virtual image?

It is an upright image formed where rays of light appear to meet or come from.

What is a real image?

It is an inverted image that is formed by the intersection of light rays; a real image can be projected on a screen.

What is a laterally inverted image?

An image which is back to front.

What is a concave mirror?

A mirror with a surface that curves inward like the inside of a bowl , converge light to one point.

What is a convex mirror?

A mirror that is curved outward like the back of a spoon, reflect light outwards.

total internal reflection

the complete reflection of a light ray back into its original medium

Define refraction of light.

It is the bending of light as it passes from one medium to another.

Define refractive index.

It is a measure of the light-bending ability of a medium (sin i / sin r).

Define critical angle.

It is the angle of incidence that produces an angle of refraction of 90 degrees (sin c = 1/n ).

What is principal axis?

It is the line passing through two centers of curvatures.

What is principal focus?

The point on the principal axis of a lens where light rays parallel to the principal axis converge after refraction

What is focal length?

the distance from the center of a lens to the focal point