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Conservation Laws
Conservation laws are extremely important in physics. They are relevant to a wide
variety of physical phenomena. They are very powerful and hence very useful. And
interestingly, they follow directly from the symmetry principles we discussed in the last
chapter. We can see this by just considering what it means if something is conserved.
If something is conserved, it does not increase or decrease; it does not change;
it does not vary. In other words, it remains invariant. So, we can give the following
de nition to conservation:
Something is conserved if we can do something to it such that afterwards it
remains invariant.
Of ...