12. Which of the following statements about ground detectors for systems that are permit. ted to operate ungrounded is not true?
a. Ground detectors are permitted to consist of a system of lamps (light bulbs).
b. Ground detectors are intended to indicate that one phase has become grounded.
c. Ground detectors are available as listed equipment. abban
d. Ground detectors must report the occurrence to a remote location.

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

Draw the engineering stress-strain curve for (a) bcc; (b) fcc metals and mark important points.

Ahot wire operates at a temperature of 200°c while the air temperature is 20°c. the hot wire element is a tungsten wire of 5 um diameter and 2 mm in length. plot using excel current, heat transfer and heat generated by the wire for air velocity varying from 1-10 m/s in steps of lm/s? matlab the sensor voltage output, resistance, or assume nu 0.989 re033pr13 take air properties at tr (200°c20°c)/2 = 110°c properties of tungsten: c 0.13 kj/kg. k 3 p 19250 kg/m k (thermal conductivity) = 174 w/m. k