# AQA Physics Unit 1 - Important Equations

AQA Physics Unit 1 - Important Equations

Some equations you WILL need for the Unit One Exam.

REMEMBER: These can be rearranged using simple Algebra. And remember to watch out for units!

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• Created by: PhilMoze
• Created on: 15-01-11 22:06

## Efficiency

EFFICIENCY (%?) = Useful energy transfer/

Total Energy Transfer

I.e 100 Watts go into a lightbulb. Only 5 Watts get's converted into light = 0.5 or 5% efficiency.

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## Energy Transfer

Energy Transferd (kWh) =  Power (kW) x

Time (hours)

I.e 7kw Shower, is on for 3 hours. 7x3 = 14 kWh

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## Cost of Electric

Total Cost =              Number of kWh (kWh) x

Cost Per kWh (hours)

I.e a family uses 500 kWh, each one costing 5p. 500x5 = 2500p or £25

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## Wave's

WaveSpeed (m/s) =  Frequency (hz) x

Wavelength (metre's)

I.e A wave has a frequency of 3000Hz, and a wavelength of 1 metre.

3000 x 1 = 3000 m/s

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## Conversion

Power (W) =     energy transferred (J)     ÷ time taken (s)

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