19. The molar specific heat at constant volume of a monatomic ideal gas on a 2-dimensional plane is (A) R B3R (E)R/2 (C)2R (D)0 20. Consider two distinguishable particles which can exist in two states with energy -e/2 or e/2. Find its internal energy U/e in the large temperature limit (i.e, kT E) (A) 1 (B)0 (C)1/2 (E) Infinity (D)3/2 21. If trace of a matrix is -8 and its determinuny ie 7. What are its possible eigen values? (A) 1,4 (B) -4,1 (E) None of the above (D) -5,-2 22. Given that: B(1, m) = f(1-x)-1yl-1dx, then , dx (@ ( (m )