Will the armour piece where I put Protection affect its effects?
If I put Protection on a Chestplate (for example) will it have a greater effect than on Boots?
Will Protection be more effective on some armour pieces than anothers?
Best Answer
I conducted an experiment to test your question(In 1.8.9) and the answer was NO.
First I tested each piece of leather armor without any effects: Boots:
Chestplate:
Helmet:
Leggings:
Each test with normal leather armor ended with the same amount of damage taken. I had jumped from a height of 11 blocks and tested each armor piece one at a time with leather so the damage would be more significant and easier to read. You could probably draw the conclusion from this, but I decided to test just to make sure. I gave myself Protection 2 leather armor and repeated the test. I used a command like this:
/give @p leather_helmet 1 0 {display: {Name: "hat"},ench: [{id: 0,lvl: 2}]}
Although the damage was decreased by half a heart the damage taken with each one on stayed the same. As a last and final test I gave myself Protection 4 armor and jumped from a height of 15 blocks to make sure that my data didn't change. 
...As I had expected the data didn't change and the damage taken was equal even on different pieces of armor. I received a damage of five hearts on each of the last jumps with the different individual armor pieces.
This test should prove that enchantments don't change the defense value depending on the armor piece within one set.
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