. Refrigerant-134a enters the coils of the evaporator of a refrigeration system as a saturated liquid– vapor mixture at a pressure of 160 kPa. The refrigerant absorbs 180 kJ of heat from the cooled
space, which is maintained at -5°C, and leaves as saturated vapor at the same pressure. Determine
(a) the entropy change of the refrigerant, (b) the entropy change of the cooled space, and (c) the
total entropy change for this process.

magnityde and direction

answer: at 24 february, 2014 the population gets twice of its initial population.

explanation:

since we have given that

the population for alpha city, t years after january 1, 2004 is given as

first we find out the initial population, i.e. t=0,

so, our quadratic equation becomes,

according to question, we have said that if the population has twice its initial population, then it becomes

so, time taken to reach this above mentioned population is given by

now, we know that time can't be negative so, we take t=9.149 years.

hence, at 24 february, 2014 the population gets twice of its initial population.