Two reason friction occurs between surfaces

Which statement is true for light passing into a medium that is more optically dense than the first medium through which it past

If 2 moles of co_2 at 2l and 500k are expanded reversibly to 20l, more work can be obtained from an adiabatic process than from an isothermal process. is the above statement true or false?

Atomic nuclei of almost all elements consist of