Chemical Engineering Gate Yearwise 


Chemical Engineering Gate 2021 Questions with Answer

Ques 40 GATE 2021

Some people suggest anti-obesity measures (AOM) such as displaying calorie information in restaurant menus. Such measures sidestep addressing the core problems that cause obesity: poverty and income inequality.
Which one of the following statements summarizes the passage?

A

The proposed AOM addresses the core problems that cause obesity.

B

If obesity reduces, poverty will naturally reduce, since obesity causes poverty.

C

AOM are addressing the core problems and are likely to succeed.

D

AOM are addressing the problem superficially.


(d) is the correct answer.

Ques 41 GATE 2021

Heat transfer coefficient for a vapor condensing as a film on a vertical surface is given by

A

Dittus-Boelter equation

B

Nusselt theory

C

Chilton-Colburn analogy

D

Sieder-Tate equation


(b) is the correct answer.

Ques 42 GATE 2021

In a double-pipe heat exchanger of 10 m length, a hot fluid flows in the annulus and a cold fluid flows in the inner pipe. The temperature profiles of the hot (Th) and cold (Tc) fluids along the length of the heat exchanger (x, such that x≥0), are given by
Th(x)=80-3x
Tc(x)=20+2x
where Th and Tc are in °C, and x is in meter.
The logarithmic mean temperature difference (in °C) is

A

24.6

B

27.9

C

30.0

D

50.0


(b) is the correct answer.

Ques 43 GATE 2021

For a shell-and-tube heat exchanger, the clean overall heat transfer coefficient is calculated as 250 W m-2K-1 for a specific process condition. It is expected that the heat exchanger may be fouled during the operation, and a fouling resistance of 0.001 m2K W-1 is prescribed. The dirt overall heat transfer coefficient is W m-2K-1.

A

100

B

150

C

200

D

250


(c) is the correct answer.

Ques 44 GATE 2021

A straight fin of uniform circular cross section and adiabatic tip has an aspect ratio (length/diameter) of 4. If the Biot number (based on radius of the fin as the characteristic length) is 0.04, the fin efficiency is _______ % (round off to nearest integer).


(43) is the correct answer.

Ques 45 GATE 2021

Consider a solid slab of thickness 2L and uniform cross section A. The volumetric rate of heat generation within the slab is ˙g(W m-3). The slab loses heat by convection at both the ends to air with heat transfer coefficient h. Assuming steady state, one-dimensional heat transfer, the temperature profile within the slab along the thickness is given by:
T(x) = (gL2)/(2k) [1-(x/L)2] + Ts for -L≤x≤L
where k is the thermal conductivity of the slab and Ts is the surface temperature. If Ts=350 K ambient air temperature T∞=300 K, and Biot number (based on L as the characteristic length) is 0.5, the maximum temperature in the slab is _______ K (round off to nearest integer).


(362) is the correct answer.

Ques 46 GATE 2021

Which of the following is NOT a standard to transmit measurement and control signals?

A

4-20 mA

B

3-15 psig

C

0-100%

D

1-5 VDC


(c) is the correct answer.

Ques 47 GATE 2021

A feedforward controller can be used only if

A

the disturbance variable can be measured

B

the disturbance variable can be manipulated

C

the disturbance variable can be ignored

D

regulatory control is not required


(a) is the correct answer.

Ques 48 GATE 2021

The inherent characteristics of three control valves P, Q and R are shown in the figure.

The CORRECT option(s) is/are

A

P is a quick opening valve

B

Q is a quick opening valve

C

P is an equal percentage valve

D

R is an equal percentage valve


(a;d) is the correct answer.

Ques 49 GATE 2021

Which of these symbols can be found in piping and instrumentation diagrams?

A

(Q) and (S) only

B

(P), (Q) and (R) only

C

(P), (R) and (S) only

D

(P), (Q), (R) and (S)


(c) is the correct answer.

Ques 50 GATE 2021

It is required to control the volume of the contents in the jacketed reactor shown in the figure.

Which one of the following schemes can be used for feedback control?

A

Measure L101 and manipulate valve V-2

B

Measure T101 and manipulate valve V-1

C

Measure L101 and manipulate valve V-3

D

Measure F101 and manipulate valve V-1


(c) is the correct answer.

Ques 51 GATE 2021

Which of the following is NOT a necessary condition for a process under closed-loop control to be stable?

A

Dead-time term(s) must be absent in the open-loop transfer function

B

Roots of the characteristic equation must have negative real part

C

All the elements in the left (first) column of the Routh array must have the same sign

D

Open-loop transfer function must have an amplitude ratio less than 1 at the critical frequency


(a) is the correct answer.

Ques 52 GATE 2021

A system has a transfer function G(s)=(3e-4s)/(12s+1). When a step change of magnitude M is given to the system input, the final value of the system output is measured to be 120. The value of M is _______.


(40) is the correct answer.

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