9. A system is given 300 calories of heat and it does 600 joules of work. How much does the internal energy of the system change in this process (J = 4.18 joules/cal)

(a)  654 Joule                           (b)  156.5 Joule (c)   ­­– 300 Joule                        (d)  – 528.2 Joule Ans. a (6)