Why does the size of the area over which a force is distributed make a difference?

As we know when on a unit area force is applied the resultant we get is pressure.  

Explanation:

Now if you suppose the force applied on a small area then all the applied force is concentrated over that area hence the pressure that is applied over that area will be more while when the same force is applied on a greater area or a larger surface the force gets distributed over that surface and would no longer be concentrated.

Hence the pressure that would be applied will be less. We can say when lesser is the area force felt will be more and vice versa.  

electrical potential energy =0.072 j

explanation:

electrical potential energy is given by

u= q δv

q= charge=6 c

δv= potential difference and is given by

δv= e d

e= electric field

d= distance=5 mm=0.005 m

δv=2.4 (0.005)=0.012 v

now electric potential energy= u= q δv

u=6 (0.012)

u=0.072 j