What makes an object opaque?
Light cannot pass through them at all, it's absorbed and reflected
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| Term | Definition |
|---|---|
| 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 |