Question

Young's modulus of elasticity for `"A"` and `"B"` are `"Y"_"A" = 1.1×10^11\ "Pa"` and `"Y"_"B" = 2.0 xx 10^11\ "Pa"`. Which is more elastic and why?

Answer 1

substance `B`

Explanation:

Young's modulus `= (Stress)/(strai n)`

Now,elasticity means the relative hindrance by an object during causing distortion of its structure i.e strain.

Now,stress means force applied per unit area i.e a measurement of pressure.

So,we can conclude that to cause a certain amount of strain of a more elastic substance we need to apply larger amount of stress.

Suppose,a material has Young's modulus `Y` and the other have `Y'`,for causing same amount of strain `x` we need to apply stress `s` for the first one and `s'` for the second one,where `s>s'`

so,for the first substance we can write,

`Y=s/x` or, `x=s/Y`

and for the second substance,

`Y'=(s')/x`

or, `x=(s')/(Y')`

so,`s/Y =(s')/(Y')`

or, `s/(s') =Y/(Y')`

As,`s>s'` so `Y>Y'`

That means a substance which is more elastic will have higher value of Young's modulus.