Question

If I completely annihilate a hair of your body that has a mass of $1\mu g$ then how much energy will I get in the process.

• A.
• B.
• C.
• D.

Answer 1

The correct option is A

Einstein's theory says that if we have a mass m then it's rest mass energy E is related to it by $m=\frac{E}{c^2}.$ Hence if we annihilate a mass m, according to this equation, the amount of energy that we'll get is :
$E=m{c}^2.$
Now we have a mass = $1\mu g.$. We will have to convert that in Kilograms first. (SI Unit my friend.)
Hence rest mass energy $E={10}^{-9}\times (3\times {10}^8)\times (3\times {10}^8)J$ Which is on calculating $9\times {10}^{7}J.$
Quite a good amount of energy!!!