Topical Test 3 Answer Key

1. DAM Question

b) (as explained on Monday, below is the answer)
The lower the opening, the greater kinetic energy the water has to spurt further.
Hence, the dam is built at the bottom as the running water has more kinetic energy to be used to generate electricity.

2. Solar Calculator

a) What kind of energy does it use?

Answer : Solar Energy or Light energy

b) from where does the solar calculator get its energy?

If your answer in (a) is Solar energy, then the source is the Sun.
If your answer in (a) is Light energy, then the source can be the Sun or Lamp.

c) state the conversion of energy that take place

Whenever we answer conversion of energy question, we need to look at how the solar calculator operates.
EXPLANATION:
To operate the solar-powered calculator, the source comes from the Sun or Light (Light or Solar energy). The calculator is an electrical device that works on electricity (Electrica energy).
Answer : Light energy / Solar energy --> Electrical energy

3. Wind turbine

a) what kind of energy does a wind turbine use?
WRONG : Wind Energy. We do not use Wind energy in our Syllabus even though we often see it in books.
Answer : Kinetic Energy from the wind.

b) how does a wind turbine generate electricity?

Whenever we answer how or why question involving energy, we need to mention the energy involved in the process.

Answer : The kinetic energy of the wind causes the rotors of the windturbine to move. As a result, the kinetic energy of the turbine is converted into kinetic energy in the generator which created electricial energy as a result.