1. Key Concepts of Physics
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Key Concepts of Physics
2016 EdExcel GCSE Physics
Topic 1
W Richards
The Weald School

2. International System of Units
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There are six basic quantities we need to know about. Their units are called S.I. units:
Base quantity
Base unit
Symbol
Length
metre m
Mass
kilogram kg
Time
second s
Current
ampere A
Temperature
Kelvin K
Amount of substance
mole
mol

3. Standard Form and prefixes
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Prefix
Symbol
Multiplier
Giga G
109
Mega M
106
Kilo K
103
Centi c
10-2
Milli m
10-3
Micro μ
10-6
Nano n
10-9
Now try these conversions:
What is 1 metre in mm?
What is 1 metre in nanometres?
What is 10mm in metres?
What is 100 micrometres in metres?
What is 100 micrometres in mm?
What is 1mm in nanometres?
0.001m or 10-3m
m or 10-9m
0.01m or 10-2m
0.0001m or 10-4m
0.1mm
1,000,000nm or 106nm

4. Other conversions and significant figures
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Other conversions and significant figures
Can you answer these questions?
What is 1KW in watts?
What is 1MW in watts?
What is 1 minute in seconds?
What is half an hour in seconds?
What is 18,765 to 3 significant figures?
What is in standard form and to 3 significant figures?
What is milliamps in amps, to 3 significant figures?
A physics lesson is one hour 20 mins long. What is this in seconds in standard form and to 3 significant figures?
1000W
106W
60s
1800s
18,800
5.48x10-3
1.54x10-4A
4.80x103s