Current And Charge

Question 1

3 effects of an electric current

Answer 1

• heating effect
• magnetic effect
• chemical effect

Question 2

Electric current

Answer 2

aka, conventional current, Is a flow of electric charge

• the path around which the charge flows is called a circuit
• an electric current in a metal conductor is a flow of electrons
• The unit of electric current is the ampere (A)
• the letter I is the symbol for electric current

• conventional current is said to flow from + to -
- in a metal, electrons actually flow in the opposite direction

Question 3

Conductor

Answer 3

A substance through which electric charge can flow

Question 4

Insulator

Answer 4

A substance through which electric charge cannot flow

Question 5

Electric charge

Answer 5

• particles that exert electrostatic forces on each other are said to be electrically charged
• the electrons are said to be negatively charged and the protons are positively charged
• The amount of positive charge on a proton is the same size as the amount of negative charge on an electron
• an electric current is charged particles moving
• The unit of electric charge is the coulomb (C)

Question 6

Size of an electric current

Answer 6

The size of an electric current in a conductor is by definition the amount of charge passing any point of that conductor per second

Question 7

Direct current (d.c.)

Answer 7

The current always flows in one direction

An electric current caused by a chemical cell or a battery is a direct current

Question 8

Alternating current (a.c.)

Answer 8

When an electric current in a circuit reverses direction every so often

Question 9

Ammeter

Answer 9

Measures the size of an electric current

• gives the size of the current in amperes
• smaller currents are measured on meters called milliammeters or micro-ammeters. A galvanometer is another word for a milliammeter or micro-ammeter
• an ammeter must be connected in series with the part of the circuit in which the current to be measured is flowing