### Tut 1 Basics

1. What is the charge of a single electron?
-1,6 x 10-19C

2. How would you make an object positively charged?
remove electrons from it

3. Two objects are positively charged. Will they attract or repel each other?
since they are like charged, they will repel

4. Object A attracts object B. If object A is negative, what is the charge of object B?
positive, since unlike charges attract

5. Name the Law and write down the equation, that can be used to calculate the magnitude of the force that exists between two charged objects.
Coulombs Law

6. Define the term electric field.
region around a charged object where some other charge will experience a force.

7. Define the term electric field strength.
this is the force exerted per unit charge
E = F/Q

8. Write down the equation to calculate the magnitude of the electric field of a point charge.

9. What is meant by saying that an object is "insulated"?
Charge cannot escape from it. Charge is trapped in it. Hence the object can be positively or negatively charged and will remain so.

10. What does it mean to say that an object is "earthed"?
It is neutral. Typically a conductor is attached from the object to the ground. Hence charge cannot stay collected on the object because they escape to the ground through this conductor. Therefore the object is neutral.

In diagram A the excess electrons got no-where to escape. Hence they remain in the dome. We say that this dome is insulated and remains negatively charged.
In diagram B, when the conductor is included, the excess electrons escape through this "earthing wire". Hence this dome becomes neutral. That is the symbol for "earthing".