5. Use the ideal gas equation pV/T = constant. The net work done is the area enclosed . The heat can be calculated using first law of thermodynamics. Work and increase in internal energy is known , hence heat can be found. However you need to know that over one cycle there is no change in temperature and therefore internal energy is constant. In the direct process Y to W the work done by the gas is the area of trapezium.
6. Use young double slit formula to find the new y' in terms of y. The D and a is the same , hence y'/y= 400/600. Hence y' = 2/3 y . To draw the fringe pattern in 2 spaces of y draw 3 spaces of y'. So a total of 7 lines should be drawn for fringe pattern of blue. To keep y constant , D'/D =600/400. D'= 1.5 D. Use ratio correctly.
