An array of 10 silicon chips, each of length l = 12 mm on a side is insulated on one surface and cooled on the opposite surface by atmospheric air in parallel flow with t
[infinity]
= 25
o
c and u
[infinity]
= 35 m/s. when in use the same electrical power is dissipated in each chip, maintaining a uniform heat flux over the entire cooled surface.

a) if the temperature of the chip may not exceed 85
o
c, what is the maximum allowable power per chip?

b) would it be preferable to orient the array normal, instead of parallel, to the air flow. explain your answer.