Physics - Elasticity Question with Solution | TestHub
Figure shows roughly how the force between two adjacent atoms in a solid varies with separation . Which statements are correct?
[1] OQ is the equilibrium separation
[2] Hooke's law is obeyed around P
[3] The potential energy of the atoms is the gradient of the graph at all points
[4] The energy to separate the atoms completely is obtained from the area enclosed below the axis of 
Options:
Answer:
Solution:
Equilibrium is where , which is at P, not Q. So [1] is false.
Near P the graph is nearly a straight line through zero force, so displacement. Hooke's law holds: [2] is true.
Force is the gradient of the - graph (with a minus sign). Potential energy is not the gradient of the - graph: [3] is false.
Work to separate the atoms , the area enclosed between the curve and the axis: [4] is true.
So 2 and 4 only: option (B).
