Physics Q5 – Power transmission | VCE Units 3 & 4 Practice – StudyPulse
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Physics VCE Units 3 & 4 Practice Question 5 – Power transmission

Q5 Physics Power transmission Unit 3 - AOS 3

Question 5

7 marks

A newly constructed residential area requires a consistent power supply of 20 MW. The local power plant generates electricity at 12 kV and is located 25 km away. The transmission lines connecting the power plant to the residential area have a total resistance of 0.25 $\Omega$ per kilometer. Analyse the effectiveness of using a step-up transformer at the power plant to increase the transmission voltage to 120 kV, followed by a step-down transformer at the residential area to reduce the voltage back to 12 kV for distribution. Quantitatively justify whether the reduced power loss warrants the investment in the transformers, given that the transformers have a fixed combined operational cost of \$5,000 per day. Assume the cost of electricity is \$0.15 per kilowatt-hour.

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About This Physics Question

This is a free VCE Units 3 & 4 Physics practice question worth 7 marks, testing your understanding of Power transmission. It falls under How are fields used in electricity generation? in Unit 3: How do fields explain motion and electricity?. Submit your answer above to receive instant AI-powered marking and personalised feedback.

Subject
Physics – Victorian Certificate of Education Units 3 & 4
Unit 3
How do fields explain motion and electricity?
Area of Study 3
How are fields used in electricity generation?
Key Knowledge
Power transmission

Unit 3 Overview

In this unit students use Newton’s laws to investigate motion in one and two dimensions. They explore the concept of the field as a model used by physicists to explain observations of motion of objects not in apparent contact. Students compare and contrast three fundamental fields – gravitational, magnetic and electric – and how they relate to one another. They consider the importance of the field to the motion of particles within the field. Students examine the production of electricity and its delivery to homes. They explore fields in relation to the transmission of electricity over large distances and in the design and operation of particle accelerators. A student-designed practical investigation involving the generation of primary data and including one continuous, independent variable related to fields, motion or light is undertaken either in Unit 3 or Unit 4, or across both Units 3 and 4, and is assessed in Unit 4, Outcome 2. The design, analysis and findings of the investigation are presented in a scientific poster format.

How are fields used in electricity generation?

In this area of study, students use empirical evidence and models of electric, magnetic and electromagnetic effects to explain how electricity is produced and delivered to homes. They explore the transformer as critical to the performance of electrical distribution systems in minimising power loss.

Key Knowledge Detail

Analyse the supply of power by considering transmission losses across transmission lines: P = I²R, and using transformers to reduce current and hence reduce losses.

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