Doubt from magnetic effect of current

Match the colum


Ans=A=p,s B=C=q,t,r, D=pp

My doubt is
How to compare energy density of wall and outside
Option R and T how pressure tend to expand.

In option T radiation pressure is acting from inside the sphere and force due to radiation pressure is towards outside so it's trying to expand the sphere and consequently the surface of the sphere. In option R I guess what they mean by expand is that the sheets will move away from each other..

For energy density, you can see by ampere's law that magnetic field inside the pipe in option P would be zero and outside the pipe would be non zero so energy would be greater outside the pipe..
For option Q if you take two diametrically opposite points on the surface of pipe , you can observe that magnetic fields due to them will add up inside the pipe as they're in the same direction and outside the pipe they're in opposite directions so magnetic field and it's energy is greater inside the pipe