List, in ascending order, the cutoff frequencies for the first ten modes of a rectangular waveguide, normalized to the cutoff frequency of the TE10 mode. (That is, for each mode, you will be calculating the cutoff frequency of that mode divided by the cutoff frequency of the TE10 mode.) Assume that a = 2b. Give numerical values for the normalized cutoff frequencies and clearly indentify the mode number and type (TM or TE) for each mode. (Note that some modes may have the same cutoff frequency.)

Steel is coated with a thin layer of ceramic to protect against corrosion. what do you expect to happen to the coating when the temperature of the steel is increased significantly? explain.

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?

The higher the astm grain-size number, the coarser the grain is. a)-true b)-false