Light

Question 1

Give 3 ways we can tell light is a form of energy?

Answer 1

1. It can do work or cause movement - Crooke’s radiometer
2. It can be converted to other forms of energy
3. Other forms of energy can be converted to light

Question 2

How can we tell light travels in straight lines?

Answer 2

1. Place 3 cards about 10cm apart in a line with holes in the middle of them in front of a candle
2. Thread string through the holes and pull tight to ensure they are in a straight line
3. The light from the candle should be clearly visible through the 3 holes
4. Move one card slightly and observe results

Question 3

What is reflection

Answer 3

The bouncing of light from a surface

Question 4

How do you show investigate the reflection of light by plane mirrors and illustrate this using a ray diagram?

Answer 4

1. Set up a ray box at an angle shining on a mirror. Place a sheet of white paper underneath everything
2. Darken the room and shine a ray of light at the plane mirror
3. Mark with a pencil two Xs on the path of the of the ray on the incident ray and the reflected ray
4. Keeping the line aimed at the same point on the mirror, increase the angle of the incident ray. The angle is the same for the reflected ray

Question 5

How do you demonstrate a simple periscope?

Answer 5

1. Set up two plane mirrors in clamps on a retort stand in front of a large block with an object on top of it
2. Set up one mirror at the bottom and one at the top with both at a 45 degree angle
3. Move your eye level to the level of the lower mirror to see the object on top

Question 6

Give 3 applications of reflection

Answer 6

Car mirrors, periscopes, shaving mirrors

Question 7

What is refraction?

Answer 7

The bending of light as it passes from one medium to another

Question 8

Give 3 applications of refraction

Answer 8

Camera lens, rainbow, forensic science