Chemical Engineering Gate Yearwise 


Chemical Engineering Gate 2018 Questions with Answer

Ques 27 GATE 2018

At a shear rate of 10 s−1, the apparent viscosity of a non-Newtonian liquid was found to be 1 Pa·s.
At a shear rate of 100 s−1, the apparent viscosity of the same liquid was found to be 0.5 Pa·s.
If the liquid follows power law behavior, the apparent viscosity (in Pa·s) at a shear stress of 10 N m−2 is _____________ (rounded off to two decimal place).


(1.00) is the correct answer.

Ques 28 GATE 2018

A set of 4 parallel lines intersect with another set of 5 parallel lines. How many parallelograms are formed?

A

20

B

48

C

60

D

72


(c) is the correct answer.

Ques 29 GATE 2018

To pass a test, a candidate needs to answer at least 2 out of 3 questions correctly. A total of 6,30,000 candidates appeared for the test. Question A was correctly answered by 3,30,000 candidates. Question B was answered correctly by 2,50,000 candidates. Question C was answered correctly by 2,60,000 candidates. Both questions A and B were answered correctly by 1,00,000 candidates. Both questions B and C were answered correctly by 90,000 candidates. Both questions A and C were answered correctly by 80,000 candidates. If the number of students answering all questions correctly is the same as the number answering none, how many candidates failed to clear the test?

A

30,000

B

2,70,000

C

3,90,000

D

4,20,000


(d) is the correct answer.

Ques 30 GATE 2018

If 𝑥2 +𝑥−1=0 what is the value of 𝑥4 + 1/ 𝑥4 ?

A

1

B

5

C

7

D

9


(c) is the correct answer.

Ques 31 GATE 2018

In a detailed study of annual crow births in India, it was found that there was relatively no growth during the period 2002 to 2004 and a sudden spike from 2004 to 2005. In another unrelated study, it was found that the revenue from cracker sales in India which remained fairly flat from 2002 to 2004, saw a sudden spike in 2005 before declining again in 2006. The solid line in the graph below refers to annual sale of crackers and the dashed line refers to the annual crow births in India. Choose the most appropriate inference from the above data.

A

There is a strong correlation between crow birth and cracker sales.

B

Cracker usage increases crow birth rate.

C

If cracker sale declines, crow birth will decline.

D

Increased birth rate of crows will cause an increase in the sale of crackers.


(a) is the correct answer.

Ques 32 GATE 2018

Segmental baffles in a 2-4 shell and tube heat exchanger

A

change the flow pattern of the tube side fluid and increase the overall heat transfer co-efficient

B

increase the heat transfer coefficient in the shell side and support the tubes

C

help to reduce the thermal expansion of the tubes and increase the heat transfer coefficient in the tube side

D

increase the number of passes in the shell side and increase the heat transfer coefficient in the tube side


(b) is the correct answer.

Ques 33 GATE 2018

An insulated storage tank contains 1000 kg liquid of specific heat 10 kJ kg−1 K−1.
The liquid is heated by saturated steam, condensing in a helical coil at a temperature of 180 °C.
The heat transfer area of the coil is 0.1 m2.
If the overall heat transfer coefficient is constant at 1000 W m−2 K−1, then the time (in hours) required to raise the temperature of the liquid in the tank from 20 °C to 80 °C is ____________ (rounded off to second decimal place).


(13.00) is the correct answer.

Ques 34 GATE 2018

The wall of a pipe of radius 1 m is at a uniform temperature of 200 °C, and is covered by insulation of thickness 0.1 m.
The ambient air outside the insulated pipe is at 20 °C and has heat transfer coefficient of 10 W m−2 K−1.
The thermal conductivity of the insulation material is 0.05 W m−1 K−1.
If the heat transfer occurs at steady state, the temperature (in °C) of the outer surface of insulation is __________ (rounded off to second decimal place).


(28.20) is the correct answer.

Ques 35 GATE 2018

Vapour bubbles are formed in the nucleate boiling regime at a frequency of 10 bubbles per second per nucleation site.
There are 100 nucleation sites per m2 of heating area.
The latent heat of vaporization and the density of vapor under the operating condition are 1000 kJ/kg and 1 kg/m3, respectively.
The diameter of each bubble is 10−3 m.
Assume that the entire heat supplied is used for vapor generation.
The heat flux (in Watt per m2 of heating area) is ______________ (rounded off to third decimal place).


(0.524) is the correct answer.

Ques 36 GATE 2018

A hot liquid is to be cooled in a 1-1 shell and tube heat exchanger from 80oC to 50oC. Cooling water enters the tube side at 30oC, and exits at 45oC. The properties of the liquids are constant. Also, the overall heat transfer coefficient is same for counter-current and co current modes. The percentage saving in heat transfer area for counter-current option with respect to the area of co-current option is __________ (rounded off to third decimal place).


(27.087) is the correct answer.

Ques 37 GATE 2018

A first-order process having a transfer function, GP = 2/7s + 1 is controlled by a proportional controller with gain of 3.2. The process time constant is in minutes. Addition of the integral control action with an integral time constant of 5 minutes leads to increase in

A

offset

B

speed of response

C

order of the closed loop system

D

proportional band


(c) is the correct answer.

Ques 38 GATE 2018

The decay ratio for a system having complex conjugate poles as
 (−1/10 + j 2/15) and (−1/10 − j 2/15) is __________.

A

7×10-1

B

8×10-2

C

9×10-3

D

10×10-4


(c) is the correct answer.

Ques 39 GATE 2018

Match the items in Column A with the items in Column B

Column A Column B
(P) Pure dead-time (I) φ = −900
(Q) Pure capacitive (II) K1 s − K2 τs+1 with K2 > τK1
(R) Inverse response (III) 0 < AR < 1
(S) First-order process with unit gain (IV) AR = 1

Here, φ denotes the phase shift, K1 and K2 the process gains, τ the time constant, and AR the amplitude ratio.

A

P-II, Q-III, R-IV, S-I

B

P-III, Q-II, R-IV, S-I

C

P-I, Q-IV, R-II, S-III

D

P-IV, Q-I, R-II, S-III


(d) is the correct answer.

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