Chemical Engineering Gate 2015 Questions with Answer

Ques 14 GATE 2015


For the matrix if is an eigenvector, the corresponding eigenvalue is ______.


(7) is the correct answer.

Ques 15 GATE 2015


Consider a linear ordinary differential equation: dy/dx + p(x)y = r(x). Functions p(x) and r(x) are defined and have a continuous first derivative. The integrating factor of this equation is non-zero. Multiplying this equation by its integrating factor converts this into a:

A

Homogeneous differential equation

B

Non-linear differential equation

C

Second order differential equation

D

Exact differential equation


(d) is the correct answer.

Ques 16 GATE 2015


A complex-valued function, f(z), given below is analytic in domain D: f(z) = u(x, y) + i v(x, y) z = x + i y Which of the following is NOT correct?

A

df/dz = &partial;v/&partial;y + i&partial;u/&partial;y

B

df/dz = &partial;u/&partial;x + i&partial;v/&partial;x

C

df/dz = &partial;v/&partial;y - i&partial;u/&partial;y

D

df/dz = &partial;v/&partial;y + i&partial;v/&partial;x


(d) is the correct answer.

Ques 17 GATE 2015


A scalar function in the xy-plane is given by φ(x, y) = x² + y². If î and ĵ are unit vectors in the x and y directions, the direction of maximum increase in the value of φ at (1,1) is along

A

-2î+2ĵ

B

2î+2ĵ

C

-2î-2ĵ

D

2î-2ĵ


(b) is the correct answer.

Ques 18 GATE 2015


A vector u = -2y î + 2x ĵ, where î and ĵ are unit vectors in x and y directions, respectively. Evaluate the line integral I = ∮ u · dr where C is a closed loop formed by connecting points (1,1), (3,1), (3,2) and (1,2) in that order. The value of I is _______.


(8) is the correct answer.

Ques 19 GATE 2015


The solution of the non-linear equation x3 - x = 0 is to be obtained using Newton-Raphson method. If the initial guess is x = 0.5, the method converges to which one of the following values:

A

-1

B

0

C

1

D

2


(b) is the correct answer.

Ques 20 GATE 2015


For complex variable z, the value of the contour integral ∮ (e-2z / (z - i) ) dz along the clockwise contour C : |z| = 2 (up to two decimal places) is _______


(0.33) is the correct answer.

Ques 21 GATE 2015


Two different liquids are flowing through different pipes of the same diameter. In the first pipe, the flow is laminar with centerline velocity, V_max,1, whereas in the second pipe, the flow is turbulent. For turbulent flow, the average velocity is 0.82 times the centerline velocity, V_max,2. For equal volumetric flow rates in both the pipes, the ratio V_max,1 / V_max,2 (up to two decimal places) is _______.


(1.64) is the correct answer.

Ques 22 GATE 2015


For uniform laminar flow over a flat plate, the thickness of the boundary layer, δ, at a distance x from the leading edge of the plate follows the relation:

A

δ(x) ∝ x-1

B

δ(x) ∝ x

C

δ(x) ∝ x1/2

D

δ(x) ∝ x-1/2


(c) is the correct answer.

Ques 23 GATE 2015


A cylindrical packed bed of height 1 m is filled with equal sized spherical particles. The particles are nonporous and have a density of 1500 kg/m³. The void fraction of the bed is 0.45. The bed is fluidized using air (density 1 kg/m³). If the acceleration due to gravity is 9.8 m/s², the pressure drop (in Pa) across the bed at incipient fluidization (up to one decimal place) is _______.


(8080.0) is the correct answer.

Ques 24 GATE 2015


For Fanning friction factor f (for flow in pipes) and drag coefficient CD (for flow over immersed bodies), which of the following statements are true?
P: f accounts only for the skin friction
Q: CD accounts only for the form friction
R: CD accounts for both skin friction and form friction
S: Both f and CD depend on the Reynolds number
T: For laminar flow through a pipe, f doubles on doubling the volumetric flow rate

A

R, S, T

B

P, Q, S

C

P, R, S

D

P, Q, S, T


(c) is the correct answer.

Ques 25 GATE 2015


A centrifugal pump delivers water at the rate of 0.22 m³/s from a reservoir at ground level to another reservoir at a height H, through a vertical pipe of 0.2 m diameter. Both the reservoirs are open to atmosphere. The power input to the pump is 90 kW and it operates with an efficiency of 75%. Data: Fanning friction factor for pipe flow is f = 0.004. Neglect other head losses. Take gravitational acceleration, g = 9.8 m/s² and density of water is 1000 kg/m³. The height H, in meters, to which the water can be delivered (up to one decimal place) is _______.


(26.0) is the correct answer.

Ques 26 GATE 2015


A spherical solid particle of 1 mm diameter is falling with a downward velocity of 1.7 mm/s through a liquid (viscosity 0.04 Pa.s) at a low Reynolds number (Stokes regime). The liquid is flowing upward at a velocity of 1 mm/s. All velocities are with respect to a stationary reference frame. Neglecting the wall effects, the drag force per unit projected area of the particle, in Pa, (up to two decimal places) is ______.


(1.29) is the correct answer.

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