What makes an object opaque?

Light cannot pass through them at all, it's absorbed and reflected

What makes an object translucent?

Only some light can pass through but it's scratted

What makes an object transparent?

Most light passes straight through

If a light ray hits a mirror at 30° to the normal, what angle will it reflect off at?

30°

Diffuse reflection happens on ____

Rough surfaces

Specular reflection happens on ____

Smooth surfaces

If you were drawing a ray diagram, where would you draw the normal line - along the mirror, or at 90° to the mirror?

90°

When light goes from air into glass, does it speed up or slow down?

Slows down

Why does light slow down in glass than in air?

Air is less dense than glass.

What does light do when entering a denser material?

It slows down

When light slows down does it bend to towards the normal, or away?

Towards

If violet light bends more than red light in a prism, what will happen to the colours as they come out -will they stay together or spread out?

Spread out

If you shine red light on a blue object, what colour will the object look?

Black

What are the secondary colours of light?

Magenta (red + blue), Cyan (green + blue), Yellow, (green + red)

If you shine green light on a yellow object, what colour will it look?

Green

If a wave has a bigger amplitude, what changes — the loudness or the pitch?

The loudness

If a wave has a shorter wavelength, will the sound be high‑pitched or low‑pitched?

High-pitched

If a wave gets taller but the wavelength stays the same, what changes — the loudness or the pitch?

The loudness

If the amplitude of a wave is 5 cm, what is the crest‑to‑trough distance?

10 cm

Which wave has the higher pitch — P or Q? Wave P - Short wavelength → high pitch Wave Q - Long wavelength → low pitch

Q

An ultrasound pulse takes 0.02 s to travel to a baby and back. The speed of sound in body tissue is 1600 m/s. How far away is the baby?

16 metres

An ultrasound pulse takes 0.1 s to travel to the ocean floor and back. The speed of sound in seawater is 1500 m/s. How deep is the ocean at that point?

75 m

If you are standing in the umbra during a solar eclipse, what do you see?

Total eclipse

What is the umbra?

The darkest part of the shadow

What is the penumbra?

The lighter art of the shadow

What is the hearing range for humans?

20 - 20, 000 Hz

What is the law of reflection?

Angle of incidence = angle of reflection

How fast does sound travel in solids?

~5000 m/s

How fast does sound travel in liquids?

~1500 m/s

How fast does sound travel in gases?

~340 m/s

How fast does light travel?

~300, 000 km/s

What type of wave is sound?

Longitudinal wave

What type of wave is sound?

Electro magnetic or transverse