**Evans SPH 4U1**

**Physics Grade 12**

**Unit 6: Electricity**

**Note 2: Mini lesson
on Charge**

**Coulomb:** We will talk more
about later but...its the unit used to measure electric charge. It is equivalent
to an excess or deficiency of **6.24 x 10 ^{18}** electrons.

Charge (q) on one electron is one
negative elementary charge = **- 1.6 x 10 ^{-19} C**

Charge (q) on one proton is one positive
elementary charge = **+ 1.6 x 10 ^{-19} C**

Quantity of electric charge:

**q = Ne **
where q is the quantity of charge in coulombs, N is the # of excess or
deficiency of electrons, e is elemental charge.

**Example 1:**

Calculate the quantity of the electric
charge on an object which has an excess of 6.0 x 10^{30} electrons. (
-9.6 x 10^{11} C)

**Example 2:**

Calculate the charge on an electroscope
that has a deficiency of 4.0 x 10^{8} electrons. (6.4 x 10^{-11}C)

**Example 3:**

Calculate the number of excess electrons
on a gold leaf electroscope which possesses -4.0 x 10^{-9} C of electric
charge.( 2.5 x 10^{10 }electrons)

**Charge Sharing: **When charged conductors of equal capacity are brought
into contact with each other and then separated, that total charge is shared
equally among the conductors.

**Example:**

Three identical spheres, having charges of 5 C, 4 C, and 12 C are brought into contact and then separated. What is the charge on each sphere afterwards? Solution: Total charge = 21 C Therefore afterwards the charge on each is 7 C.