To increase the speed of response of a pressure spring liquid or gas expansion thermometer, the clearance space between the thermometer bulb and the thermal well should not be filled with

The root locus plot of the roots of the characteristics equation of a closed loop system having the open loop transfer function $$\frac{{{\text{K}}\left( {{\text{s}} + 1} \right)}}{{2\left( {2{\text{s}} + 1} \right)\left( {3{\text{s}} + 1} \right)}}$$    will have a definite number of loci for variation of K from 0 to $$\infty $$. The number of loci is

A. 1

B. 3

C. 4

D. 2

Phase lag of the frequency response of a second order system to a sinusoidal forcing function

A. Is 30°

B. Is 90° at the most

C. Approaches 180° asymptotically

D. Is 120°

Which of the following is not classified as a thermo electric pyrometer?

A. Resistance thermometer

B. Thermocouple

C. Optical pyrometer (disappearing filament type)

D. Radiation pyrometer

The temperature of tempering oil baths maintained at 400°C during heat treatment of steel is measured by a/an __________ thermocouple.

A. Chromel-alumel

B. Iron-constantan

C. Platinum-platinum/rhodium

D. None of these