Science 8 · Unit 6: Light · Cambridge Lower Secondary Science Stage 8

Questions

1. 1. What name is given to any transparent substance light can pass through?

   • a regular
   • a medium
   • an average
   • a normal
   Check

2. 2. What causes refraction?

   • a mirror
   • a change in the speed of light
   • a change in the shape of light
   • a change in the colour of light
   Check

3. 3. When light passes from air into water, what happens to its speed?

   • It speeds up.
   • It stays the same.
   • It slows down.
   • It stops.
   Check

4. 4. When light passes from glass into air, what happens to its speed?

   • It slows down.
   • It stops.
   • It stays the same.
   • It speeds up.
   Check

5. 5. When light passes from water into glass, what happens to its speed?

   • It doubles.
   • It slows down.
   • It speeds up.
   • It stays the same.
   Check

6. 6. In which substance does light travel most slowly?

   • diamond
   • corn oil
   • air
   • water
   Check

7. 7. Between which two substances would there be most refraction?

   • air and diamond
   • corn oil and glycerol
   • air and water
   • water and corn oil
   Check

8. 8. Between which two substances would there be no refraction?

   • corn oil and glycerol
   • air and diamond
   • air and water
   • water and diamond
   Check

9. 9. When light slows down entering a new medium, which way does it bend?

   • along the surface
   • towards the normal
   • straight back
   • away from the normal
   Check

10. 10. When light speeds up entering a new medium, which way does it bend?

    • back on itself
    • towards the normal
    • away from the normal
    • straight on always
    Check

11. 11. Light enters glass along the normal. What happens?

    • It reflects back.
    • It slows down but doesn't change direction.
    • It bends a lot.
    • It stops.
    Check

12. 12. Why can't you see clearly through a window covered in raindrops?

    • The glass melts.
    • Raindrops make light.
    • The raindrops refract light in many directions.
    • Raindrops are opaque.
    Check

13. 13. Light passes through a parallel-sided glass block from air and back to air. How does it leave?

    • at 90° to the incoming ray
    • straight back
    • much brighter
    • parallel to the incoming ray, but shifted sideways
    Check

14. 14. What is the angle of refraction?

    • the angle of the mirror
    • the angle between the refracted ray and the normal
    • the angle of incidence
    • the angle between the ray and the surface
    Check

15. 15. What is the speed of light in air?

    • 30 km/s
    • 3000 km/s
    • 300 000 km/s
    • 300 km/s
    Check

16. 16. Light travels at 300 000 km/s in air, 225 000 km/s in water and 200 000 km/s in glass. In which does it travel slowest?

    • water
    • air
    • it is the same in all three
    • glass
    Check

17. 17. A coin at the bottom of a cup is just out of sight. Water is poured in and the coin comes into view. Why?

    • The water makes the coin bigger.
    • Light from the coin bends as it leaves the water.
    • The water lifts the coin up.
    • Light reflects off the cup's side.
    Check

18. 18. Why do windscreen wipers help a driver see clearly in the rain?

    • Wet glass reflects all the light.
    • Raindrops make light travel faster.
    • Raindrops are opaque.
    • Each raindrop refracts light in a different direction.
    Check