MODULE 6 IQ 3

Question 1

What is Magnetic flux

Answer 1

A measure of the total magnetic field passing through a particular area

Question 2

Magnetic flux equation

Answer 2

φ = BAcosθ

φ: magnetic flux (Weber, Wb)
B: magnetic field strength or magnetic field density (Tesla, T)
A: area (m^2)
θ: angle between the magnetic field and the normal to the area

Question 3

Faraday’s Law

Answer 3

“The induced EMF, in a closed circuit, is directly proportional to the rate of change of magnetic flux”

Question 4

EMF is the same as

Answer 4

Voltage

Question 5

Faraday’s law equation

Answer 5

EMF = ε = -n x Δφ/Δt

ε: induced EMF (V)
N: number of loops
Δφ: change in magnetic flux (Wb)
Δt: change in time (s)

Question 6

Lenz’s Law

Answer 6

“An induced EMF in a closed circuit always gives rise to a current whose magnetic field will oppose the original change in flux”

Question 7

What are eddy currents?

Answer 7

When a metal plate experiences a change in magnetic flux, it induces a special type of current known as eddy currents

Question 8

What are transformers?

Answer 8

Allow generated AC voltage to be either increased or decreased before it is used. Function on the basis of mutual induction whereby a changing current in one coil causes an induced EMF in the vicinity of another coil.

Question 9

Equation for transformers

Answer 9

V(p)/V(s) = n(p)/n(s) = I(s)/I(p)

V: voltage
N: number of coils
I: current
P: primary coil
S: secondary coil

Question 10

Types of transformers

Answer 10

Step up transformers, step down transformers

Question 11

What are step up transformers

Answer 11

Increases the primary voltage, outputs a smaller current in the secondary coil

Question 12

What are step down transformers

Answer 12

Decreases the primary voltage, outputs a large current in the secondary coil

Question 13

Electromagnetic braking

Answer 13

Applies both the principle of electromagnetic induction and the motor effect