Chapter 3- Light Flashcards
What is light?
A form of radiation energy we observe with our eyes
What are luminescent objects and give an example.
Objects which radiate their own light. Eg:the sun
What are illuminated objects and give an example.
Objects that reflect the light shone on them. The light falls on our eyes. Eg: book
What is the speed of light?
300000 km/sec
8 mins to get to earth from the sun
Million times faster than sound
Fill in the missing word:
The sun radiates 1. __________ light. White light is a combination of 2. ____________ 3. ____________ of light. The 4. ________ is formed when white light from the sun 5. _______________ on the water droplets at just the right angle for the light to disperse into a band of colours called the 6. ________________. The colour reflected the least is 7. ____________ and the colour reflected most is 8. _____________.
- White
- Different
- Colours
- Rainbow
- Falls
- Spectrum of light
- Red
- Violet
Why is light called a wave?
Because when it travels, it moves up and down in a regular pattern
What light has a short wavelength and what light has a long wavelength?
Red: long wavelength
Violet: short wavelength
What are light rays that fall on objects Called?
Light rays that fall on objects are called INCIDENT RAYS which can be absorbed, reflected and passed through
What is the refraction of light?
The changing of path of a light ray as it moves from one optical medium to another.
Distinguish between a concave and convex light.
Concave:
- Another name is converging mirrors
- Can be objected on screen
- Concave means hollowed in
- Spherical mirror~reflecting surface and centre of curvature reflect on the same side
Convex:
- Another name is diverging mirror
- Can’t be objected on screen
- Convex means curved/rounded
- Spherical mirror~reflecting surface and centre of curvature reflect on opposite sides.
