GATE Overflow for GATE XE - Recent questions and answers in Food Engineering

GATE XE 2026 | Question: 26

Tue, 24 Feb 2026 15:48:19 +0000

A vertical jet of diameter $d_{1}$ strikes a horizontal plate with a velocity $U$, as shown in the figure. The plate has a hole of diameter $d_{2}(<d_{1})$ concentric to the flow through which a portion of fluid passes with same velocity $\text{U}$. The remaining fluid moves radially outward along the plate. If $\text{F}$ is the force acting vertically upward to hold the horizontal plate at its initial place, which of the following statements is/are true?

Radially outward flow has no effect on $F$.
$F$ decreases as $d_{2}$ decreases keeping other parameters unchanged.
$F$ increases as $U$ increases keeping other parameters unchanged.
$F$ remains constant as $d_{1}$ increases keeping other parameters unchanged.

GATE XE 2026 | Question: 49

Tue, 24 Feb 2026 15:45:51 +0000

Which of the following statements is/are applicable to Fick's second law:

Concentration changes with time
Steady state condition prevails
Diffusion is time dependent
Concentration profile is linear

GATE XE 2026 | Question: 126

Tue, 24 Feb 2026 15:31:18 +0000

Which one of the following statements is true for a high-pressure homogenizer?

Homogenization takes place only due to uniform mixing of solid and liquid
Solid particles in the suspension are disintegrated due to the high shear rate exerted by the liquid
High pressure steam is injected to dissolve the solids
Solid particles in the suspension are compressed into a cake under high pressure

GATE XE 2026 | Question: 130

Tue, 24 Feb 2026 15:29:39 +0000

A wet solid, fed to a dryer at a rate of $5 \mathrm{~kg} / \mathrm{s}$, is dried using hot air. In this process its moisture content is reduced from $25 \%$ to $15 \%$. The rate of moisture removal is $\_\_\_\_$ $\mathrm{kg/s}$. (Round off to two decimal places)

GATE XE 2026 | Question: 140

Tue, 24 Feb 2026 15:25:24 +0000

During constant pressure cake filteration, for an incompressible cake deposited uniformly over a constant filter surface area,

the cake resistance remains constant
the cake resistance increases in proportion to the cake thickness
the filtration rate remains constant
the filtration rate decreases with time

GATE XE 2025 | Question: 64

Sun, 04 May 2025 19:06:56 +0000

At $873 \: \mathrm{K}$ , hydrogen diffuses under steady state condition through a $5\: \mathrm{mm}$ thick palladium sheet with a cross-sectional area of $0.3 \mathrm{~m}^{2}$. The concentrations of hydrogen at high and low pressure ends of the sheet are $3 \mathrm{~kg} \mathrm{~m}^{-3}$ and $0.5 \mathrm{~kg} \mathrm{~m}^{-3}$, respectively. The amount of hydrogen (in $\mathrm{kg}$ per day) passing through the sheet is (rounded off to two decimal places) $\_\_\_\_\_\_$

Given: At $873 \: \mathrm{K}$, diffusivity of hydrogen $=1.8 \times 10^{-8} \mathrm{~m}^{2} \mathrm{~s}^{-1}$

GATE XE 2025 | Question: 152

Sun, 04 May 2025 15:30:16 +0000

A fruit juice is concentrated using an ultrafiltration membrane. A feed stream at $10 \mathrm{~kg} / \mathrm{min}$ with $6 \%$ total solids (by weight) is increased to $20 \%$ total solids (by weight). The membrane tube has $10 \: \mathrm{cm}$ inside diameter and the pressure difference across the membrane is $2000 \: \mathrm{ kPa}$. If the permeability constant of the membrane is $5 \times 10^{-5} \mathrm{~kg} \text{ water} / ( \mathrm{m}^{2} \: \mathrm{kPa} \: \mathrm{s}$ ), the length of membrane tube (in $\mathrm{m}$ ) is $\_\_\_\_\_\_$ (rounded off to $2$ decimal places)

GATE XE 2025 | Question: 153

Sun, 04 May 2025 15:30:15 +0000

In a typical grinding operation, $80 \%$ of the feed material passes through a sieve opening of $4.75 \: \mathrm{mm}$; whereas, $80 \%$ of the ground product passes through $0.5 \: \mathrm{mm}$ opening. If the power required to grind $2 \: \mathrm{tonnes} / \mathrm{h}$ of the feed material is $3.8 \: \mathrm{kW}$, the work index of the material is $\_\_\_\_\_\_\_$ (rounded off to $2$ decimal places)

GATE XE 2025 | Question: 171

Sun, 04 May 2025 15:26:31 +0000

In hot weather, a human body cools by the evaporation of sweat from its skin. The amount of water that must evaporate to cool the body by $1^{\circ} \mathrm{C}$ is $\_\_\_\_\_\_\_$ $\%$ of the body mass. (Round off to two decimal places.)

[Assume that latent heat of vaporization of water is $2.25 \times 10^{6} \mathrm{~J} \mathrm{~kg}^{-1}$ and specific heat capacities of both human body and liquid water is $4.2 \times 10^{3} \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~kg}^{-1}$.]

GATE XE 2024 | Question: 28

Sun, 21 Jul 2024 16:42:24 +0000

A circular water jet of diameter $50$ mm impinges with a velocity of $18 \mathrm{~m} / \mathrm{s}$ normal to a plate. The density of water is $1000 \mathrm{~kg} / \mathrm{m}^{3}$ and gravity force is neglected.

The magnitude of net force $\text{(in N , rounded off to two decimal places)}$ imparted by the jet on the stationary plate is _____________.

GATE XE 2024 | Question: 53

Sun, 21 Jul 2024 16:42:04 +0000

A $2$ mm thick palladium sheet of $1000 \mathrm{~mm}^{2}$ cross section is used as a diffusional membrane to purify hydrogen. The hydrogen concentration is maintained at a steady state with $\boldsymbol{c}_{\boldsymbol{h}}=1.5 \mathrm{~kg} \mathrm{~m}^{-3}$ and $\boldsymbol{c}_{\boldsymbol{l}}=0.3 \mathrm{~kg} \mathrm{~m}^{-3}$ on the two sides of the membrane as shown in the figure below.

The rate of hydrogen purification is $\text{(in units of $\mathrm{kg} \mathrm{hr}^{-1}$ )}$ _________ $\times 10^{-6}$ $\text{(rounded off to one decimal place)}$.

Given: The diffusion coefficient of hydrogen in palladium is $1.0 \times 10^{-8} \mathrm{~m}^{2} \mathrm{~s}^{-1}$

GATE XE 2024 | Question: 97

Sun, 21 Jul 2024 16:41:24 +0000

$100$ moles of moist air at $70 \%$ relative humidity is cooled from $70^{\circ} \mathrm{C}$ to $50^{\circ} \mathrm{C}$ at a constant pressure of $1$ bar . The vapour pressures of water are given in the table. The number of moles of water left in the moist air at the end of this process is _________ $\text{(rounded off to two decimal places)}$.

Temperature $\left({ }^{\circ} \mathbf{C}\right)$	Vapour Pressure (kPa)
$50$	$12.34$
$70$	$31.16$

GATE XE 2024 | Question: 140

Sun, 21 Jul 2024 16:40:51 +0000

Which of the following statements is/ are true?

Hagen-Poiseuille's law is used for calculation of molecular diffusion.
Fick's law is used for calculation of energy requirement in size reduction.
Rittinger's law is used for calculation of energy requirement in size reduction.
Stokes law is used for derivation of terminal velocity.

GATE XE 2024 | Question: 143

Sun, 21 Jul 2024 16:40:49 +0000

A tubular bowl centrifuge is used to separate an aqueous phase from an oil phase. The radii of outlets of the light and heavy liquids are set at $4.5$ cm and $4.6$ cm, respectively. The radius in cm of the neutral zone in the centrifuge is ________ $\text{(round off to 2 decimal places)}$. Assume the density of the aqueous phase is $950 \mathrm{~kg} \cdot \mathrm{m}^{-3}$ and that of oil is $900 \mathrm{~kg} \cdot \mathrm{m}^{-3}$.

GATE XE 2023 | Question: 26

Wed, 14 Feb 2024 18:09:55 +0000

Q. 36 A water jet (density $=1000 \mathrm{~kg} / \mathrm{m}^{3}$ ) is approaching a vertical plate, having an
orifice at the center, as shown in the figure. While a part of the jet passes through
the orifice, remainder flows along the plate. Neglect friction and assume both the
inlet and exit jets to have circular cross-sections. If $\mathrm{V}=5 \mathrm{~m} / \mathrm{s}, D=100 \mathrm{~mm}$ and
$d=25 \mathrm{~mm}$, magnitude of the horizontal force (in $\mathrm{N}$, rounded off to one decimal
place) required to hold the plate in its position is

GATE XE 2023 | Question: 139

Wed, 14 Feb 2024 18:08:09 +0000

\begin{tabular}{l|l}
Q.149 & Identify the correct pair(s) of governing law with respective process operation. \\
\hline

& Stoke's law - Mass transfer \\
\hline
& Kirchhoff's law - Radiation heat transfer \\
\hline
& Fourier's law - Conduction heat transfer \\
& Fick's law - Molecular diffusion
\end{tabular}

GATE XE 2023 | Question: 140

Wed, 14 Feb 2024 18:08:08 +0000

Q. 150 A hammer mill is used to grind blackgram. The size distribution of the blackgram is such that $80 \%$ passes through a $6-$ mesh (particle size $=3.36 \mathrm{~mm}$ ) screen. The power requirement to produce a powder, $80 \%$ of which passes through a 45 -mesh (particle size $=0.354 \mathrm{~mm}$ ) screen is $4.5 \mathrm{~kW}$. The power in $\mathrm{kW}$ required to produce a finer powder $80 \%$ of which passes through a $60-$ mesh (particle size $=0.25 \mathrm{~mm}$ ) will be (rounded off to 2 decimal places). Assume the feed rate to the mill is constant in both the cases. Use Bond's law of size reduction.

GATE XE 2022 | Question: 20

Fri, 17 Feb 2023 06:52:24 +0000

A $10 \mathrm{~kg}$ mass placed on an infinitely long horizontal massless flat platform is to be supported by a steady vertical water jet as shown in the figure. The diameter of the jet is $5 \mathrm{~cm}$. What minimum average velocity is required to hold the mass in place?
Assume $\rho_{\text {water }}=1000 \mathrm{~kg} / \mathrm{m}^{3}, g=10 \frac{\mathrm{m}}{\mathrm{s}^{2}}$ and $\pi=3.14$. Neglect friction.
(Round off to two decimal places)

GATE XE 2022 | Question: 29

Fri, 17 Feb 2023 06:52:16 +0000

Consider a lawn sprinkler with horizontal arms of radius, $a=10 \mathrm{~cm}$ which has water introduced vertically through the centre, as shown in the figure. The exit area of the jet is $25 \mathrm{~cm}^2$ and the jet velocity is $1 \mathrm{~m} / \mathrm{s}$. The water is ejected orthogonal to the sprinkler arm and the jet makes an angle of $60^{\circ}$ with the horizontal plane. Find the torque $(in \mathrm{N}-\mathrm{m})$ required to hold the sprinkler stationary.

Consider water density $1000 \mathrm{~kg} / \mathrm{m}^3$. Neglect the effects of friction and gravity.
$\text{(Round off to two decimal places)}$

GATE XE 2022 | Question: 51

Fri, 17 Feb 2023 06:51:58 +0000

It is known that component A diffuses into a solid to a depth of $10 \mu \mathrm{m}$ in 1 hour at $300 \mathrm{~K}$. Treat diffusion in one dimension. The time taken for A to diffuse to the same depth at $600 \mathrm{~K}$ _________ is seconds.

$\text{(Round off to 1 decimal)}$.

Diffusivity of $\mathrm{A}$ in the solid is given by
\[
D_{A}=D_{A}^{0} \exp \left(-\frac{E_{a}}{k_{B} T}\right)
\]
$D_{A}^{0}$ : Diffusivity coefficient
$E_{a}:$ Activation energy $=0.3 \mathrm{eV}$
$k_{B}$ : Boltzmann's constant $=8.62 \times 10^{-5} \mathrm{eV} / \mathrm{K}$
$T:$ Absolute temperature