EnergyHigh Exam FrequencyAQA

Efficiency

Revise Efficiency in Energy for GCSE Physics with 19 exam-style questions and 4 flashcards. This is a high-frequency exam topic, so students should expect to explain it clearly under timed conditions.

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The Leaky Bucket Problem

Introduction 2

What Is Efficiency?

Deep Dive 3

Sankey Diagrams

Deep Dive 4

Why Is Efficiency Never 100%?

How It Works 5

Efficiency of Common Devices

Comparison 6

Key Definitions

Definitions 7

Key Facts — Efficiency

Key Facts 8

Worked Examples

Worked Example 9

Common Misconceptions

Misconceptions 10

Memory Aids

Memory Aid 11

Exam Focus: Efficiency

Exam Focus 12

Exam Tips for Efficiency

Exam Tips 13

Knowledge Organiser: Efficiency

Summary

Sample Flashcards

As a decimal

0.85 (between 0 and 1)

As a percentage

85% (multiply decimal by 100)

Exam questions for Efficiency

Which equation correctly defines efficiency?

A. efficiency = total input energy / useful output energy
B. efficiency = useful output energy transfer / total input energy transfer
C. efficiency = wasted energy / total input energy
D. efficiency = total input energy / wasted energy

1 markfoundation

Explain one method that can be used to reduce unwanted energy transfers in a machine and state how it reduces waste.

2 marksstandard

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