Everything Science Grade 10

CHAPTER 16. ELECTROSTATICS 16.4

See the summary presentation ( Presentation: VPfqd at http://www.everythingscience.co.za))

• There are two kinds of charge: positive and negative.


• Positive charge is carried by protons in the nucleus.


• Negative charge is carried by electrons.


• Objects can bepositivelycharged,negativelycharged orneutral.


• Objects that are neutral have equal numbers of positive and negative charge.


• Unlike charges are attracted to each other and like charges are repelled from each
  other.


• Charge is neither created nor destroyed, it can only be transferred.


• Charge is measured in coulombs (C).


• Charge is quantised in units of the charge of an electron 1. 6 × 10 −^19 C,Q=nqe.


• Conductors allow charge to move through them easily.


• Insulators do not allow charge to move through them easily.


• Identical, conducting spheres in contact share their charge according to:

Q=Q^1 + 2 Q^2

Physical Quantities

Quantity Unit name Unit symbol

Charge (Q) coulomb C

Charge on the electron (qe) coulomb C

Table 16.2: Units used inelectrostatics

Chapter 16 End of chapter exercises

1. What are the two types of charge called?

2. Provide evidence for the existence of two types of charge.

3. Fill in the blanks: The electrostatic force between like charges is while

the electrostatic force between opposite charges is.

4. I have two positively charged metal balls placed 2 m apart.

a. Is the electrostatic force between the balls attractive or repulsive?

Physics: Electricity and Magnetism 277