How many VCAA Physics questions cover How are fields used in electricity generation??

AusGrader has 67 VCAA Physics questions on How are fields used in electricity generation?, all with instant AI grading and detailed marking feedback.

VCAA (VCE) Physics — How are fields used in electricity generation? Questions & Answers | AusGrader

Q13

2023

QCAA

Paper 1

1 mark

Q13

1 mark

A magnet moving through a coil of wire will induce a current with a magnetic field

A

parallel to the electric field.

B

opposite in direction to the change in flux.

C

inversely proportional to the electromotive force.

D

that will continue to fluctuate once the magnet is removed.

Q1

2022

QCAA

Paper 1

1 mark

Q1

1 mark

Electromotive force is

A

the production of voltage across an electrical conductor due to its dynamic interaction with a magnetic field.

B

a difference in potential that tends to give rise to an electric current.

C

the repulsion experienced by two negatively charged particles.

D

one of the four fundamental forces.

Q21

2021

QCAA

Paper 1

3 marks

Q21

3 marks

Explain how transformers work in terms of Faraday’s law and electromagnetic induction.

Alternating current passing through the first coil creates a magnetic flux. This magnetic flux induces an EMF in the secondary coil. The induced EMF is proportional to the number of coils and the rate of change of the magnetic flux.

Marking Criteria

Descriptor	Marks
recognises that alternating current creates a changing magnetic flux	1
recognises that EMF is induced in the second coil by the changing magnetic flux in the first coil	1
identifies that the induced EMF is proportional to the number of coils and the rate of change of magnetic flux	1

Q1

2024

QCAA

Paper 2

4 marks

Q1

4 marks

A coil of wire with 100 turns and a radius of 1.4 cm is placed perpendicular to a magnetic field of strength 0.510 T. The magnetic field strength is then changed to 0.030 T in 0.020 s.

Calculate the magnitude of electromotive force (emf) (V) induced in the coil. Show your working.

$r = 1.4 \text{ cm} = 0.014 \text{ m}$

$A = \pi r^2 = \pi \times 0.014^2 \approx 6.16 \times 10^{-4} \text{ m}^2$

$\text{emf} = - \frac{n \Delta (B A_{\perp})}{\Delta t}$

$= - \frac{100 \times (0.030 - 0.510) \times (6.16 \times 10^{-4})}{0.020}$

$= 1.48$

Magnitude of emf = $1.5 \text{ V}$

Marking Criteria

Descriptor	Marks
converts the radius to SI units (from cm to m)	1
determines the area of the coil	1
recognises the scenario relates to induction of an electromotive force by using the equation	1
calculates emf	1

Q25

2024

QCAA

Paper 1

4 marks

Q25

A transformer with a turns ratio of 48:1 is set up to reduce a 240 V input.

Q25a

3 marks

Explain how a transformer works in terms of Faraday’s Law and electromagnetic induction.

According to Faraday's Law, when the magnetic flux linking a circuit changes, an emf is induced in the circuit proportional to the rate of change of the flux linkage.
Therefore, in the transformer, the changing voltage in the primary coil will affect the rate of change of the magnetic flux in the second coil. Although the circuits aren't connected, a current will be induced in the secondary circuit.

Marking Criteria

Descriptor	Marks
describes Faraday's Law	1
explains changing voltage in the primary coil affects rate of change of magnetic flux in secondary coil	1
explains an AC voltage is induced in the secondary coil by electromagnetic induction	1

Q25b

1 mark

Determine the output voltage.
Voltage = ______ V

A current will be induced in the second coil generating an AC voltage of:
$\frac{V_p}{V_s} = \frac{n_p}{n_s}$
$\frac{240}{V_s} = \frac{48}{1}$
$V_s = 5 \text{ V}$

Marking Criteria

Descriptor	Marks
determines secondary voltage to be 5 V	1

VCAA Physics How are fields used in electricity generation?

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