Light

Light and Colour

What are objects that give out light energy called?

Objects that emit light energy are called sources.

What must happen for us to see an object?

Light must enter our eyes.

What are the three things that can happen to light when it interacts with an object?

Absorbed, transmitted, reflected.

Which type of material completely blocks light?

Opaque materials.

Which type of material allows light to pass through clearly?

Transparent materials.

Which type of material allows some light to pass through but distorts the image?

Translucent materials.

Why do we see lightning before we hear thunder?

Light travels much faster than sound.

What is the speed of light?

3,000,000,000 m/s.

What is the speed of sound in air?

330 m/s in air.

What occurs when light bounces off a surface?

Reflection.

When drawing light reflecting off a mirror, what is the normal line?

A dashed line perpendicular to the surface.

How do you differentiate the reflective side of a mirror from the back in diagrams?

The reflective side is flat, the back has slanted lines.

What is the incident ray?

Light going towards the object.

What is the reflected ray?

Light going towards the eye.

What is the relationship between the angle of incidence and the angle of reflection?

Angle of incidence equals the angle of reflection.

What affects how light is reflected?

Mirrors and rough surfaces.

What does a rough surface do to the light?

Splits light in various directions.

What is it known as when light is split in various directions?

Diffuse reflection.

Why can we see an image in undisturbed water?

The water acts like a flat surface, causing specular reflection.

What is the bending of light as it passes from one substance to another called?

Refraction.

What is the point at which light changes from one substance to another called?

The interface.

What happens when light enters a new substance at an angle?

The direction light travels in will change.

Is glass or air more dense?

Glass is more dense.

What effect does refraction have on the image?

The object appears to be in two places at once.

What are the two types of lenses discussed?

Concave and convex.

What is a concave lens?

Light hits an inwards curving surface.

What does a concave lens do to light?

Cause light rays to spread out.

What is a convex lens?

Light hits an outwards curving surface.

What does a convex lens do to light?

Cause light rays to get closer.

What are the three primary colors of light?

Red, green, blue.