# Practice Test: Question Set - 03

**1. Water is entering a storage tank at a temperature**

*T*_{0}and flow rate*Q*_{0}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*A*_{0}. The model that describes the dynamic variation of temperature of water in the tank with time is given as:- (A)

*Q*

_{0}(

*T*

_{0}-

*T*) =

*A*.

_{c}*h*(

*dT*/

*dt*)

- (B)

*Q*

_{0}

*T*

_{0}-

*QT*=

*A*.

_{c}*h*(

*dT*/

*dt*)

- (C)

*Q*(

*T*

_{0}-

*T*) =

*A*.

_{c}*h*(

*dT*/

*dt*)

- (D)

*Q*(

*T*

_{0}-

*T*) =

*A*.

_{c}*(*

*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 (2*s*+ 1) (3*s*+ 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 1/2**

*s*. The controller proposed to be used in an integral controller with transfer function 1/*T*_{1}*s*. 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’?**

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