134. Thermistor is a bulk semiconductor device having temperature coefficient of resistance which is
A. high and negative
B. low and negative
C. high and positive
D. low and positive
135. The device used to measure flow of air around an aeroplane is
A. venturimeter
B. orifice
C. rotameter
D. anemometer
136. In a pitot tube
A. velocity head is converted into pressure head
B. pressure head is converted into velocity head
C. velocity head is converted into datum head
D. differential pressure is produced across the tube
137. Hot wire anemometer is used to measure
A. pressure of gauges
B. liquid discharge
C. very low pressures
D. gas velocities
138. The function of the reference electrode in a pH meter is
A. to measure average pH value
B. to produce a constant voltage
C. to provide temperature compensation
D. to produce a constant current
139. Piezo-electric quartz crystal can be used to measure
A. temperature
B. velocity
C. acceleration
D. flow
140. Main advantage of semiconductor strain gauge over resistive strain gauge is its
A. high sensitivity
B. low sensitivity
C. smaller size
D. better ruggedness
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