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CIE A Level Physics复习笔记1.1.3 Homogeneity of Physical Equations & Powers of Ten

Category: A-level课程, 教材笔记, 福利干货 Date: 2022年8月16日上午10:32

Homogeneity of Physical Equations

An important skill is to be able to check the homogeneity of physical equations using the SI base units
The units on either side of the equation should be the same
To check the homogeneity of physical equations:
- Check the units on both sides of an equation
- Determine if they are equal
- If they do not match, the equation will need to be adjusted

1.1.2-Homogeneity-of-Physical-Equations

How to check the homogeneity of physical equations

Powers of Ten

Physical quantities can span a huge range of values
For example, the diameter of an atom is about 10^–10 m (0.0000000001 m), whereas the width of a galaxy may be about 10²¹ m (1000000000000000000000 m)
This is a difference of 31 powers of ten
Powers of ten are numbers that can be achieved by multiplying 10 times itself
It is useful to know the prefixes for certain powers of ten

Powers of Ten Table

1.1.2-Powers-of-Ten-Table-

Exam Tip

You will often see very large or very small numbers categorised by powers of ten, so it is very important you become familiar with these as getting these prefixes wrong is a very common exam mistake!

转载自savemyexams