Question

A student writes the einstein mass -energy equivalence relation as e=c^2/m where mass is m and cis the speed of light in fre space .Is this relation is correct or not

Answer 1

Answer ⇒ No, it is incorrect.

Explanation ⇒ For checking the equation to be correct check by the method of dimension. If it is not cxorrect by dimension then it is surely incorrect.

But if it is correct by dimension, then it is not sure whether it is correct or not.

Unit of Energy = Joule

= Nm

= [MLT⁻²] × [L]

= [ML²T⁻²]

Now, On R.H.S.,

c = speed of light = m/s.

= LT⁻¹

∴ c²/M = L²T⁻²M⁻¹

We can see that LHS is not exactly the same as R.H.S., there is actually an difference between terms of mass.

Means, this formula is wrong.

Correct formula is E = mc².

For Checking it is correct or not, follow dimension analysis. But it is not sure so read Mass-Energy concept and its derivation.

Hope it helps.

Answer 2

No it's not incorrect.