Section 6: Magnetism and electromagnetism

a) Units
b) Magnetism
c) Electromagnetism
e) Electromagnetic induction

a) Units

Examiner's Expectation: 6.1 Students will be assessed on their ability to use the following units: ampere (A), volt (V), watt (W).

S.NoQuantity with DefinitionunitSymbol of unit
1 Current

Definition: Flow of charges per unit time or Flow of electrons per unit time.

Note: For exams write the definition in words as

Current = ΔQ / Δt

Where "Q" represents Charges and "t" represents times

Ampere

A
2 Voltage

Definition: Work done per unit Charge OR

               Energy Transferred per unit Charge

Note: Since work done = Energy Transferred.

Note: For exam:

Voltage = Work done / Charge

                  or

Voltage = Energy Transferred / Charge

symbolically,

V = W / Q

or V = E /Q

 

  Joules / Columb                   or

Volts

However, Volt is a standard unit. But both are same as

1 Joules/columb = 1 Volt

J/C

or

V

1 J/C = 1 V

3 Power

Definition: Energy transferred per second 

                      OR

            Work done per second

For exams, write definition in words as follows

Power = Energy Transferred / Time

P = E /t

Joules / Second

OR

Watt

However, the standard unit is Watt. But both are same

1 Joules/Second = 1 Watt

J/s

OR

W

1 J/S = 1 W