Static Electricity Flashcards
What causes static electricity?
An imbalance of electrical charges (positive and negative).
Objects that gain electrons exhibit a _______ charge
Negative
Objects that lose electrons exhibit a _________ charge
Positive
What does static mean?
Not moving
What are electrostatic charges?
Voltage developed by an excess or lack of electrons on an object.
What kind of material do electrostatic charges usually build on?
Insulator materials
What is a electroscope?
A device that is used to determine whether an object contains a positive or negative charge.
What must be done before an electroscope can be used?
It must be charged. This can be done by touching the ball with an object that has a known charge.
How can you use an electroscope to measure the polarity of a charged object?
You must put the object close to but not touching the ball. If the charged object has a negative charge, the leaves on the scope will move farther apart. If the charged object has a positive charge, the leaves will move closer together.
What is the best example of natural static electricity?
Lightning
True or False. Clouds can contain both positive and negative charges at the same time.
True
Whether a lightning bolt travels from ground to cloud or cloud to ground is determined by __________
Which one is positive and which one is negative. Current always travels from negative to positive
What is the average voltage of a lightning bolt?
15,000,000 volts
What are two devices used for lightning protection?
Lightning rods and Lightning arrestors
How do lightning rods work?
They provide an easy path to ground for current flow. When a protected object is struck, the lightning rod bleeds the lightning discharge to ground before the protected object can be harmed.
How do lightning arrestors work?
They are grounded at one end, and the other end is brought close (but not touching) to the object to be protected. If the protected object is struck, the high voltage of the lightning arcs across the lightning arrestor and bleeds to the ground.
What are three examples of nuisance static charges?
- The static charge that accumulates on vehicles as they move through dry air.
- The static charge that accumulates on a person’s body as he or she walks across a carpet
- The static charge that accumulates on clothes in a dryer
What are two examples of useful static charges?
- Static charge in spray painting
- Static charge in dry copy machines
