In a 3x3m square flat horizontal solar collector the outside of the glass cover of the collector is at 40 c and the ambient air is at 10 c with wind parallel to the surface of the collector at velocity of 10m/s. find: a. the rate of heat loss by convection from the glass b. the friction coefficient, cf on the glass c. if the wind dies down find the rate of heat transfer from the glass assuming its outside temperature remains the same.

When at a point two solid phase changes to one solid phase on cooling then it is known as a) eutectoid point b) eutectic point c) peritectic point d) peritectoid point

Athin walled concentric tube exchanger is used to cool engine oil from 160°c to 60°c with water that is available at 25°c acting as a coolant. the oil and water flow rates are each at 2 kg/s, and the diameter of the inner tube is 0.5 m and the corresponding value of the overall heat transfer coefficient is 250 w/m2. oc. how long must the heat exchanger be to accomplish the desired cooling? cpwater=4.187 kj/kg-candcpengine el=2.035 kj/kg·°c, oil . 120]

With increases in magnification, which of the following occur? a. the field of view decreases. b. the ambient illumination decreases. c. the larger parts can be measured. d. the eyepiece must be raised.