Practice Test: Question Set - 03
1. Water is entering a storage tank at a temperature T0 and flow rate Q0 and leaving at a flow rate Q and temperature T. There are negligible heat losses in the tank. The area of cross-section of the tank is A0. The model that describes the dynamic variation of temperature of water in the tank with time is given as:
- (A) Q0(T0 - T)
= Ac . h
(dT/dt)
- (B) Q0T0 - QT = Ac . h (dT/dt)
- (C) Q(T0 - T)
= Ac . h
(dT/dt)
- (D) Q(T0 - T)
= Ac . (dTH/dt)
2. The root locus plot of the roots of the characteristics equation of a closed loop system having the open loop transfer function K (s + 1)/[2 (2s + 1) (3s + 1)] will have a definite number of loci for variation of K from 0 to ∞. The number of loci is
- (A) 1
- (B) 2
- (C) 3
- (D) 4
3. Nitrogen gas constant volume thermometer is suitable for measuring a temperature of _________ °C.
- (A) 0-100
- (B) < 0
- (C) > 100
- (D) > 50
4. Which of the following filled system expansion thermometers has the lowest positive temperature measurement capability?
- (A) Mercury in glass thermometer
- (B) Alcohol in glass thermometer
- (C) Fused metal (Na or K) in steel thermometer
- (D) Nitrogen in steel thermometer
5. Mercury thermometer can be used to measure the temperature upto _________ °C.
- (A) 100
- (B) 250
- (C) 350
- (D) 750
6. Working principle of mercury in glass thermometer is
- (A) Volumetric expansion
- (B) Pressure rise with temperature
- (C) Linear expansion
- (D) None of these
7. In a closed loop system, the process to be controlled is an integrating process with transfer function 1/2s. The controller proposed to be used in an integral controller with transfer function 1/T1s. When a step change in set point is applied to such a closed loop system, the controlled variable will exhibit
- (A) Overdamped response
- (B) Underdamped response
- (C) Undamped response
- (D) Unstable response
8. The Laplace transform of exp(at), where a > 0, is defined only for the Laplace parameter, s > a since
- (A) The function is exponential
- (B) The Laplace transform of integral of exp(at) has finite values only
for s > a
- (C) The Laplace transform integral of exp(at) has
initial values only for s > a
- (D) The function exp(at) is piece-wise continuous only for s > a
9. A typical example of a physical system with under damped characteristic is a
- (A) U-tube manometer
- (B) Spring loaded diaphragm valve
- (C) CSTR with first order reaction
- (D) Thermocouple kept immersed in a liquid filled
thermowell
10. Temperature of _________ cannot be measured by an optical or radiation pyrometer.
- (A) Hot blast (air) from stoves
- (B) Molten slag flowing out of blast furnace
- (C) Combustion space in boilers
- (D) Rotary limestone calcination kiln
11. "A control system is unstable, if the open loop frequency response exhibits an amplitude ratio exceeding unity at the crossover frequency." This is _________ criterion.
- (A) Bode stability
- (B) Nyquist
- (C) Routh stability
- (D) None of these
12. Platinum resistance thermometer can be used upto antimony point which is _________ °C, and is the temperature of equilibrium between solid antimony & liquid antimony at normal atmospheric pressure.
- (A) 961.93
- (B) 630.74
- (C) 1064.43
- (D) 1261.93
13. In a second order under damped system, the
- (A) Time required for the response of first reach
its ultimate value is called the response time
- (B) Overshoot (which is a measure of how much the response exceeds the
ultimate value) increase with the decrease of damping co-efficient
- (C) Decay ratio (which is the ratio of the sizes of successive peaks) is
equal to the reciprocal of overshoot
- (D) None of these
14. Which of the following thermocouples has the least temperature measurement range?
- (A) Copper-constantan
- (B) Chromel-alumel
- (C) Platinum-platinum/rhodium
- (D) Iron-constantan
15. Which is the symbol for ‘pneumatic control valve’?
