# 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?

Mar 18, 2018

substance $B$

#### Explanation:

Young's modulus $= \frac{S t r e s s}{s t r a i n}$

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,

$Y = \frac{s}{x}$ or, $x = \frac{s}{Y}$

and for the second substance,

$Y ' = \frac{s '}{x}$

or, $x = \frac{s '}{Y '}$

so,$\frac{s}{Y} = \frac{s '}{Y '}$

or, $\frac{s}{s '} = \frac{Y}{Y '}$

As,$s > s '$ so $Y > Y '$

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