Question

1. what do fuel cells, batteries, and solar cells have in common?

a. they all produce static electricity
b. they are all sources of direct current
c. they are all sources of alternating current
d. they can all be used to power automobiles

1. what can you infer about this source of electricity?

a. it is a source of alternating current
b. it is a source of direct current
c. it is a source of static electricity
d. it is a source of electromagnetic radiation

1. how does alternating current differ from direct current?

a. alternating current produces more voltage than direct current
b. alternating current always flows in the same direction; the direction of a direct current switches back and forth
c. direct current produces more voltage than alternating current
d. direct current always flows in the same direction; the direction of an alternating current switches back and forth

1. how does electricity travel from power plants to your house?

a. it travels through the air as electromagnetic waves
b. through a series of generators
c. through a series of many transformers
d. through transmission wires

1. what is the function of every generator on earth?

a. changing wind energy into electrical energy
b. changing heat energy into electrical energy
c. changing mechanical energy into electrical energy
d. changing solar energy into electrical energy

1. how does a generator create current?

a. by using an electromagnet
b. by using an internal combustion engine
c. by using a fan
d. by using energy from the sun

1. place the following events in sequence: a) voltage is increased by a transformer; b) voltage is decreased by a transformer; c) electrical current enters your home

a. a, b, c
b. b, a, c
c. a, c, b
d. b, c, a

1. which of the following are sources of mechanical energy?

a. cars and trucks
b. radios and televisions
c. transmission lines and transformers
d. wind and fossil fuels

1. what is the main function of a turbine?

a. producing a magnetic field
b. spinning
c. reducing the voltage of an electrical current
d. increasing the voltage of an electrical current

1. what is one possible reason why its a good idea to conserve electricity?

a. it is often produced by burning fossil fuels, which are a polluting, non - renewable resource.
b. power companies only give each home a limited amount of electricity every day.
c. using too much electricity can start dangerous electrical fires.
d. using too much electricity can cause power plants to break down.

Explanation:

1. Fuel cells, batteries, and solar cells are all sources of direct - current. They provide a steady flow of electric charge in one direction.
2. Without seeing the specific source in question 2, assuming a common battery - like symbol, it is a source of direct current.
3. The key difference between direct and alternating current is that direct current always flows in the same direction, while alternating current switches back and forth.
4. Electricity travels from power plants to houses through transmission wires.
5. The function of a generator is to change mechanical energy into electrical energy.
6. A generator creates current by using an electromagnet. It works on the principle of electromagnetic induction.
7. Electricity from power plants has its voltage increased by a transformer for long - distance transmission, then decreased by a transformer before entering homes. So the sequence is A, C, B.
8. Wind and fossil fuels are sources of mechanical energy. Wind can turn turbines and fossil fuels can be used in engines to produce mechanical motion.
9. The main function of a turbine is spinning, which is part of the process to convert mechanical energy into electrical energy in a power - generation setup.
10. Conserving electricity is a good idea because it is often produced by burning fossil fuels, which are a polluting, non - renewable resource.

Answer:

1. b. They are all sources of direct current
2. b. It is a source of direct current
3. d. Direct current always flows in the same direction; the direction of an alternating current switches back and forth
4. d. Through transmission wires
5. c. Changing mechanical energy into electrical energy
6. a. By using an electromagnet
7. c. A, C, B
8. d. Wind and fossil fuels
9. b. Spinning
10. a. It is often produced by burning fossil fuels, which are a polluting, non - renewable resource.