Colour (Light)

Question 1

What is white light made of?
A: All the colours of the visible spectrum mixed together.

2.
Q: What happens when white light hits a red object?
A: The red object reflects red light and absorbs all the other colours.

3.
Q: What are the primary colours of light?
A: Red, green, and blue.

4.
Q: What colour do you see when all three primary colours mix?
A: White.

🔄 Refraction
5.
Q: What is refraction?
A: When light bends as it passes from one material to another (like air to glass).

6.
Q: Why does refraction happen?
A: Because light travels at different speeds in different materials.

7.
Q: What happens when light enters a denser material (like air → glass)?
A: It slows down and bends towards the normal.

8.
Q: What happens when light leaves a denser material?
A: It speeds up and bends away from the normal.

🌐 Electromagnetic Spectrum
9.
Q: What is the electromagnetic spectrum?
A: A range of waves that all travel at the same speed in a vacuum but have different wavelengths and frequencies.

10.
Q: Name the electromagnetic spectrum in order from longest to shortest wavelength.
A: Radio, microwave, infrared, visible, ultraviolet, X-rays, gamma rays.

11.
Q: Which EM waves are used in mobile phones?
A: Microwaves.

12.
Q: Which EM waves can cause sunburn?
A: Ultraviolet (UV) rays.

🎵 Sound & Vibration
13.
Q: How is sound made?
A: By vibrations that travel through a medium (like air or water).

14.
Q: Can sound travel through a vacuum?
A: No — sound needs a medium to travel through.

🌊 Describing Waves
15.
Q: What is amplitude?
A: The height of the wave from the middle to the top — it shows how loud or strong the wave is.

16.
Q: What is wavelength?
A: The distance from one wave peak to the next.

17.
Q: What is frequency?
A: The number of waves that pass a point per second. Measured in hertz (Hz).

18.
Q: What is wave speed?
A: How fast the wave moves — calculated with:
wave speed = frequency × wavelength

👂 Sensing Waves
19.
Q: How do we hear sound?
A: Vibrations from the air move the eardrum, which sends signals to the brain.

20.
Q: Why do some sounds hurt your ears?
A: They have a very high amplitude (loudness) or frequency (pitch).

🏃 Speed of Sound
21.
Q: Is sound faster in air, water, or solid?
A: Solids > liquids > gases (sound is fastest in solids).

22.
Q: What’s the approximate speed of sound in air?
A: Around 343 m/s.

🔁 Reflection
23.
Q: What is the law of reflection?
A: The angle of incidence = angle of reflection.

24.
Q: What type of surface gives a clear reflection?
A: A smooth, shiny surface (like a mirror).

Question 2

💡 Flashcard 1 (Understanding)
Q: What is the difference between specular and diffuse reflection?
A:

Specular: smooth surface, light reflects in one direction

Diffuse: rough surface, light reflects in many directions

🧠 Flashcard 2 (Sneaky)
Q: Does diffuse reflection break the law of reflection? Explain.
A: No — each ray still reflects with angle in = angle out, but the rough surface means rays reflect in different directions, so it appears scattered.

🧪 Flashcard 3 (Application)
Q: Why can you see yourself in a mirror but not on a wooden table?
A: Mirror = smooth → specular reflection (clear image).
Wood = rough → diffuse reflection (no image).

🔁 Flashcard 4 (Concept Check)
Q: Light bends towards the normal when moving into a ________ material.
A: Denser

🧐 Flashcard 5 (Sneaky)
Q: A ray of light hits glass head-on (at 90°). Will it bend?
A: No — it will slow down, but not bend.