急! F.3 Physics!
- Light is reflected by ____________________. Light rays ____________________.
- An apple looks red under sunlight. What does it looks like in a completely dark room under blue light ? Explain briefly.
- What is a spectrum?
- What is a refraction?
- Does white light pure light ? Explain briefly.
- JLv 51 十年前最愛解答
1. Mirror / smooth surface
2. Black in colour.
Red apple only reflects red light.
Since blue light is absorbed by the apple,
no colour of light is reflected.
So the apple looks black in colour.
3. A group which behaves similar is called spectrum
e.g. colour spectrum: red, orange, yellow, green, blue, indigo & violet. ALL are colour of light and visible.
4. Refraction is the changing in the wave speed whenever the wave propagates from one medium to another.
If the angle of incidence is NOT = 0, then the direction of wave travel is also changing.
5. White light is a MIXTURE of 7 colours of light.
we can separate white light into 7 colours of light by passing through a white light ray into a glass prism. A colour spectrum is observed after refraction. This experiment is called 'Dispersion of white light'.