After effects of elasticity are maximum for

If a load of $9 \, kg$ is suspended on a wire,the increase in length is $4.5 \, mm$. The force constant of the wire is

The elasticity of Invar:

What is stress? Give its two definitions.

Check if the following statements are True or False:
$(a)$ Shear modulus of liquid is infinite.
$(b)$ For a given load (external force),steel is more deformed than rubber.
$(c)$ When a solid body is beaten,rolled,heated,or cooled,its elastic properties are affected.

The property of a material which opposes the change in shape,volume,or length is called