Tube pitch is the _______________ of tube diameters and the clearances?

A. 0.38-0.78
B. 0.5-50
C. 100-1000
D. 5-50

A. W/m
B. W/m2
C. W/°K
D. W/m°K

A. 0.25 D
B. 0.50 D
C. 0.75 D
D. None of these

A. A higher capacity
B. A lower capacity
C. Lower economy
D. None of these

A. Forced convection
B. Steady state conduction
C. Monochromatic radiation
D. None of these

A. Zero
B. Unity
C. Same for all wavelengths
D. Different for all wavelengths