# Basic Electricity Worksheet

## Basic Electricity

• #### Question 1

What is the purpose of the switch shown in this schematic diagram?

• #### Question 2

What difference will it make if the switch is located in either of these two alternate locations in the circuit?

• #### Question 3

Does this switch (in the closed state) have a low resistance or a high resistance between its terminals?

• #### Question 4

How might you use a meter (or a conductivity/continuity tester) to determine whether this electrical switch is in the open or closed state?

• #### Question 5

Determine if the light bulb will de-energize for each of the following breaks in the circuit. Consider just one break at a time:

Choose one option for each point:
• A: de-energize / no effect
• B: de-energize / no effect
• C: de-energize / no effect
• D: de-energize / no effect
• E: de-energize / no effect
• F: de-energize / no effect
• #### Question 6

Shown here is a simplified representation of an atom: the smallest division of matter that may be isolated through physical or chemical methods.

Inside of each atom are several smaller bits of matter called particles. Identify the three different types of “elementary” particles inside an atom, their electrical properties, and their respective locations within the atom.

• #### Question 7

Different types of atoms are distinguished by different numbers of elementary particles within them. Determine the numbers of elementary particles within each of these types of atoms:

• Carbon
• Hydrogen
• Helium
• Aluminum

Hint: look up each of these elements on a periodic table.

• #### Question 8

Of the three types of “elementary particles” constituting atoms, determine which type(s) influence the following properties of an element:

• The chemical identity of the atoms (whether it is an atom of nitrogen, iron, silver, or some other element).
• The mass of the atom.
• The electrical charge of the atom.
• Whether or not it is radioactive (spontaneous disintegration of the nucleus).
• #### Question 9

The Greek word for amber (fossilized resin) is elektron. Explain how this came to be the word describing a certain type of subatomic particle (electron).

• #### Question 10

What does it mean for an object to have an electric charge? Give an example of an object receiving an electric charge, and describe how that charged object might behave.

• #### Question 11

How many electrons are contained in one coulomb of charge?

• #### Question 12

What is happening when two objects are rubbed together and static electricity results?

• #### Question 13

It is much easier to electrically “charge” an atom than it is to alter its chemical identity (say, from lead into gold). What does this fact indicate about the relative mobility of the elementary particles within an atom?

• #### Question 14

Explain what the electrical terms voltage, current, and resistance mean, using your own words.

• #### Question 15

Describe what “electricity” is, in your own words.

• #### Question 16

What is the difference between materials classified as conductors versus those classified as insulators, in the electrical sense of these words?

• #### Question 17

Identify several substances that are good conductors of electricity, and several substances that are good insulators of electricity.

• #### Question 18

In the simplest terms you can think of, define what an electrical circuit is.

• #### Question 19

What is the difference between DC and AC electricity? Identify some common sources of each type of electricity.

• #### Question 20

Suppose you are building a cabin far away from electric power service, but you desire to have electricity available to energize light bulbs, a radio, a computer, and other useful devices. Determine at least three different ways you could generate electrical power to supply the electric power needs at this cabin.

• #### Question 21

Where does the electricity come from that powers your home, or your school, or the streetlights along roads, or the many business establishments in your city? You will find that there are many different sources and types of sources of electrical power. In each case, try to determine where the ultimate source of that energy is.

For example, in a hydroelectric dam, the electricity is generated when falling water spins a turbine, which turns an electromechanical generator. But what continually drives the water to its “uphill” location so that the process is continuous? What is the ultimate source of energy that is being harnessed by the dam?

• #### Question 22

Given a battery and a light bulb, show how you would connect these two devices together with wire so as to energize the light bulb:

• #### Question 23

Draw an electrical schematic diagram of a circuit where a battery provides electrical energy to a light bulb.

• #### Question 24

Most electrical wire is covered in a rubber or plastic coating called insulation. What is the purpose of having this “insulation” covering the metal wire?

• #### Question 25

In the early days of electrical wiring, wires used to be insulated with cotton. This is no longer accepted practice. Explain why.

• #### Question 26

How could a battery, a light bulb, and some lengths of metal wire be used as a conductivity tester, to test the ability of different objects to conduct electricity?

• #### Question 27

Suppose we had a long length of electrical cable (flexible tubing containing multiple wires) that we suspected had some broken wires in it. Design a simple testing circuit that could be used to check each of the cable’s wires individually.

• #### Question 28

How long will it take for the light bulb to receive electrical power once the battery is connected to the rest of the circuit?

• #### Question 29

A 22-gauge metal wire three feet in length contains approximately 28.96 ×1021 “free” electrons within its volume. Suppose this wire is placed in an electric circuit conducting a current equal to 6.25 ×1018 electrons per second. That is, if you were able to choose a spot along the length of this wire and were able to count electrons as they drifted by that spot, you would tally 6,250,000,000,000,000,000 electrons passing by each second. (This is a reasonable rate for electric current in a wire of this size.)

Calculate the average velocity of electrons through this wire.

• #### Question 30

What do the symbols with the question marks next to them refer to? In the circuit shown, would the light bulb be energized?

• #### Question 31

Shown here is a simplified representation of an electrical power plant and a house, with the source of electricity shown as a battery, and the only electrical “load” in the house being a single light bulb:

Why would anyone use two wires to conduct electricity from a power plant to a house, as shown, when they could simply use one wire and a pair of ground connections, like this?

• #### Question 32

What, exactly, is a short circuit? What does it mean if a circuit becomes shorted? How does this differ from an open circuit?

• #### Question 33

What would have to happen in this circuit for it to become shorted? In other words, determine how to make a short circuit using the components shown here:

• #### Question 34

When lightning strikes, nearby magnetic compass needles may be seen to jerk in response to the electrical discharge. No compass needle deflection results during the accumulation of electrostatic charge preceding the lightning bolt, but only when the bolt actually strikes. What does this phenomenon indicate about voltage, current, and magnetism?

• #### Question 35

Just as electricity may be harnessed to produce magnetism, magnetism may also be harnessed to produce electricity. The latter process is known as electromagnetic induction. Design a simple experiment to explore the phenomenon of electromagnetic induction.

• #### Question 36

A large audio speaker may serve to demonstrate both the principles of electromagnetism and of electromagnetic induction. Explain how this may be done.

• #### Question 37

What do you think might happen if someone were to gently tap on the cone of one of these speakers? What would the other speaker do? In terms of electromagnetism and electromagnetic induction, explain what is happening.

• #### Question 38

Suppose someone mechanically couples an electric motor to an electric generator, then electrically couples the two devices together in an effort to make a perpetual-motion machine:

Why won’t this assembly spin forever, once started?