Voltage, Current, and Resistance

Basic Electricity

• Question 1

Voltage is commonly defined as “electrical pressure.” The unit of the volt, however, may be defined in terms of more fundamental physical units. What are these units, and how do they relate to the unit of the volt?

• Question 2

Electric current is measured in the unit of the ampere, or amp. What is the physical definition for this unit? What fundamental quantities constitute 1 ampere of electric current?

• Question 3

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

• Question 4

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

• Question 5

What units of measurement are used to express quantities of voltage, current, and resistance?

• Question 6

How many physical points must be referenced when speaking of the following electrical quantities?

• Voltage
• Current
• Resistance

In other words, does it make sense to speak of voltage at a single point, or between two points, or between three points, etc.? Does it make sense to speak of current at a single point, between two points, between three points, etc.?

• Question 7

Lightning is a natural, electrical phenomenon. It is caused by the accumulation of a large electrical charge over time resulting from air, dust, and water droplets transporting small electrical charges.

Explain how the terms voltage, current, and resistance relate to the process of lightning. In other words, use these three terms to explain the cycle of charge accumulation and lightning discharge.

• Question 8

Is it possible to have a condition where an electrical voltage exists, but no electric current exists? Conversely, is it possible to have a condition where an electric current exists without an accompanying voltage? Explain your answers, and give practical examples where the stated conditions are indeed possible.

• Question 9

Voltage is also known by another name: electromotive force, or EMF. Explain what this other name for voltage means.

• Question 10

Suppose a battery outputs a voltage of 9 volts. Using algebra, calculate how many joules of energy are imparted to every individual electron moving through this battery.

• Question 11

What is the difference between DC and AC electricity?

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