Electrostatics and Electric Fields Test Review

Explain: c. Charging by Induction

A charged object is brought close to a neutral conductor but does not touch it. This causes the charges to separate in the conductor leaving one side positive and the other negative - but there is no transfer of electrons.

Explain: d. Charge Polarization

A charged object is brought close to a neutral insulator but does not touch it. This causes the electrons in the atoms on the surface of the insulator to polarize. Each atom will now have a positive and a negative side - but there is no transfer of electrons.

Explain: b. Charging by Conduction (contact)

A charged object touches a neutral object causing a transfer of electrons from one object to the other. The result is both objects will now be charged the same

3. What is Coulomb's Law?

A law that states that the Electrostatic Force between two charges is directly proportional to the product of the two charges and inversely proportional to the square of the distance between the two charges.

11. A negatively charged object (attracts, repels, has no effect) on a neutral object.

A negatively charged object attracts a neutral object. Neutral objects are attracted to any type of charged object.

20. How does a positive object lose its charge?

A positive object loses its charge by gaining electrons

17. How does an atom become charged? How does an object like a balloon become charged?

An atom becomes charged by losing or gaining electrons. Objects become charged by transferring charges from one object to another.

16. Why is an atom neutral? Why is an object like a balloon neutral

An atom is neutral because the number of protons (positive charges) is equal to the number of electrons (negative charges) so there is zero net charge. Most objects - like a balloon are neutral because their total number of positive and negative charges are equal or balanced.

12. What is an electric field and where is it located?

An electric field is a "storehouse" of energy located around any charged object.

15. What is an electroscope? What is a Van de Graaff Generator?

An electroscope is a device used to detect and measure charge. A Van de Graaff generator is an electrostatic generator that collects and holds high voltages on a metal globe.

4. What is Conservation of Charge?

Charge is not created or destroyed. This means that the total of all charges (positive and negative) in the entire universe remains the same. They just move about from one place to another or from one object to another.

6. What is the SI unit for: a. Charge? " b. Electric Potential Energy? c. Electric Potential?

Coulombs which is abbreviated "C Joules which is abbreviated "J" Volts which is abbreviated "v"

13. (Electrons, Protons, Neutrons) are collected on the surface of the Van de Graaff generator. What happens to these particles when you touch the Van de Graaff? Why does your hair stand up?

Electrons are the only particles that are free to move from one location to another Your hair stands up because each strand of hair is now charged with the same type of charge and like charges repel each other.

19. What is grounding?

Grounding refers to the process of making a charged object become neutral. If an object is positive electrons will flow into it from the ground to make it neutral. If an object is negative electrons will flow out of it into the ground to make it neutral.

7. What are electric field lines?

Imaginary lines (vectors) drawn to represent the strength and the direction of an electric field

2. Like charges (attract, repel), unlike charges (attract, repel).

Like charges repel, unlike charges attract.

18. Make sure to know how neutral objects interact with charged objects

Neutral objects are always attracted to a charged object - both positive and negative.

10. Why does the electric potential energy of a positively charged object increase when you move it away from a negatively charged object?

The opposite charges want to attract to each other. If you move them away from each other that will require work. When work is done this will increase the potential energy.

8. How is the strength of an electric field indicated with electric field lines?

The strength of the electric field is indicated by the spacing of the electric field lines. The closer the lines are together, the stronger the electric field.

1. If you scuff electrons from your feet while walking across a rug, are you now negatively charged or positively charged? EXPLAIN

This is an example of charging an object by "Friction". If electrons are taken from you that means you are losing negative charges which will leave you positively charged.

9. Define electric potential energy.

This is the energy charged objects have when work is done to change their location. It is energy based on the position or location of the charges. The amount of charge also makes a difference

Explain: a. Charging by Friction

Two objects rub against each other which causes electrons to be stripped from one object to the other. The result is one object will now have a negative charge and the other will have a positive charge.

5. What property makes a. metal a good conductor b. rubber a good insulator?

The atoms in metal do not hold on to their electrons very well. Their electrons are free to move about and flow through the conductor. The atoms in an insulator hold on very tightly to their electrons and will not allow them to move about.