The number of vacancies in some hypothetical metal increases by a factor of 3 when the temperature is increased from 915 ˚C to 1160 ˚C. Calculate the energy for vacancy formation (in J/mol) assuming that the density of the metal remains the same over this temperature range.

Aquick transition of the operating speed of a shaft from its critical speed will whirl amplitude. (a) increase (b) limit (c) not affect (d) zero

Refrigerant-134a enters the compressor of a refrigerator as superheated vapor at 0.14 mpa and -10°c at a rate of 0.05 ka/s and leaves at 0.8 mpa and 50°c. the refrigerant is cooied in the condenser to 0.72 mpa and 26'c. it is then throttled to 0.15 mpa. sketch the t-s diagram for the system and evaluate: 6) the rate of heat removai from the refrigerated space (kw), it) the power input to the compressor (kw), ii) the isentropic efficiency of the compressor (%), and iv) the cop of the refrigerator.

Which of the following is the most important advantage of a large field of view? a. allows larger areas to be examined b. relieves eyestrain c. minimizes parallax errors. d. increases precision in proportion to the in- crease in field of view