Charge and current

Question 1

What is electric current?

Answer 1

The rate of flow of charge

Question 2

What is the equation for electric current?

Answer 2

I=Q/t

Question 3

What is a charge carrier?

Answer 3

Anything with an electric charge

Question 4

What is the elementary charge on an electron or proton?

Answer 4

1.6 x 10 -19

Question 5

What two factors can increase the electric current?

Answer 5

The amount of electrons moving past a given point each second (greater cross sectional area of the wire)
The same number of electrons moving faster through the wire

Question 6

What direction is conventional current?

Answer 6

From a positive terminal to a negative one

Question 7

What are liquids that can carry electric current called?

Answer 7

Electrolytes

Question 8

What is Kirchhoff’s first law?

Answer 8

At any point in an electric circuit, the sum of the current going into a given point is the same as the sum of current going out of the point

Question 9

Define the conservation of charge

Answer 9

Electric charge can neither be created or destroyed. The amount of charge in the universe is a constant.

Question 10

What is number density?

Answer 10

The number of free charge carriers per unit volume

Question 11

How does the number density of the material affect its ability to conduct?

Answer 11

The greater the number density of the material, the greater amount of free electrons per cubic metre. This means that the conductivity of the metal increases

Question 12

Which has the highest number density: conductors, semi conductors or insulators?

Answer 12

Conductors have the highest number density. Insulators have the lowest number density and semi conductors are situated in the middle

Question 13

How fast do charge carriers move?

Answer 13

When you turn on a light, it is not the speed of the charge carriers which turns the light on instantly. In a wire, electrons repeatedly collide with the fixed ions. It is when the electrons move all at once which turns the light on