two technicians are discussing catalytic converters technician a says that the exhaust mixture must fluctuate between rich and lean mixture for the best l efficiently technician b says that the air fuel mixture must be leaner than 14:7:1 for best performance from a three way catalytic converter who is correct

The mass flow rate of the fluid remains constant in all steady flow process. a)- true b)- false

Apipe with an outside diameter of 15 cm is exposed to an ambient air and surrounding temperature of -20°c. the pipe has an outer surface temperature of 65°c and an emissivity of 0.85. if the rate of heat loss from the pipe surface is 0.95 kw per meter of length, the external convective heat transfer coefficient (h) is: (a) 12.5 w/m"k (b) 18.6 w/mk (c) 23.7 w/mk (d) 27.9 w/mk (e) 33.5 w/mk

The thermal expansion or contraction of a given metal is a function of the f a)-density b)-initial temperature c)- temperature difference d)- linear coefficient of thermal expansion e)- final temperature f)- original length