How much energy is 200 MeV ? And how much destruction can it cause ?
OK, I might be criticize for the way I'm answering this, but I am going to do it anyway because I'm trying to get you to understand and figure things out yourself, and also to examine what you are asking.
What do you think if someone asks you "How much money is $20?".
Essentially, that is what you are asking in the first part of your post. 200 MeV IS how much energy that you have there! "eV" is a unit of energy, the same way "$" is a unit of money in, say, the US (you don't like "$", replace it with your favorite unit of currency).
Now, you may want to know how many Joules of energy is 200 MeV. In that case, it is a matter of changing units, the same way I want to change $20 into, say Japanese Yen.
As for "destruction", this is highly vague. I can shoot 200 MeV of energy into many things over a period of time without causing even the slightest damage. One 200 MeV electron hitting a beam pipe of an accelerator doesn't cause significant damage.
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