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Engineering Properties of Agricultural Produce(8)Evaporation and Drying(15)Size Reduction and Material Handling(15)Processing of Agriculture Produce(1)Storage Systems(4)

Engineering Properties of Agricultural Produce

8 Questions

GATE→2026→Agricultural Process Engineering→Engineering Properties of Agricultural Produce

Q1

MCQ[1 Mark]

Air carrying dust particles enters a cyclone separator of 800 mm diameter at a tangential velocity of 30 m.s−1 near the wall. The average diameter of the dust particles is 100 µm. The separation factor is nearest to (Take g = 9.81 m.s−2) (A) 229.36 (B) 611.62 (C) 485.72 (D) 3.75

(A)

229.36

(B)

611.62

(C)

485.72

(D)

3.75

Explanation

GATE→2026→Agricultural Process Engineering→Engineering Properties of Agricultural Produce

Q2

MCQ[1 Mark]

Mechanical model/method NOT related to rheological behaviour of food products is known as (A) Liebman’s method (B) Newton’s model (C) Maxwell’s model (D) Saint-Venant’s model

(A)

Liebman’s method

(B)

Newton’s model

(C)

Maxwell’s model

(D)

Saint-Venant’s model

Explanation

GATE→2026→Agricultural Process Engineering→Engineering Properties of Agricultural Produce

Q3

MCQ[2 Marks]

The ratio of moisture content on wet basis to moisture content on dry basis for wheat grain is 4:5. The ratio of weight of dry matter to weight of water in the grain is (A) 4:1 (B) 4:5 (C) 1:4 (D) 5:4

(A)

4:1

(B)

4:5

(C)

1:4

(D)

5:4

Explanation

GATE→2026→Agricultural Process Engineering→Engineering Properties of Agricultural Produce

Q4

MCQ[2 Marks]

In grinding of black pepper, 80% feed passes through 6 mm screen, and 80% product passes through 0.5 mm screen. The gross energy required is 10 kW.h per ton of material. Assuming Bond’s law holds good, and for the same feed conditions, if 80% product passes through 0.2 mm screen, the energy required, in kW.h per ton of material, is nearest to (A) 18.17 (B) 9.09 (C) 5.50 (D) 11.00

(A)

18.17

(B)

9.09

(C)

5.50

(D)

11.00

Explanation

GATE→2026→Agricultural Process Engineering→Engineering Properties of Agricultural Produce

Q5

MCQ[2 Marks]

Mass fractions of carbohydrate, protein, fat, ash, and water in banana are 0.220, 0.010, 0.005, 0.015, and 0.750, respectively. The density of carbohydrate, protein, fat, ash, and water are 1550, 1220, 900, 610, and 1000 kg.m−3, respectively. The density of banana, in kg.m−3, is nearest to (A) 1116.85 (B) 1056.05 (C) 1000.00 (D) 1107.70

(A)

1116.85

(B)

1056.05

(C)

1000.00

(D)

1107.70

Explanation

GATE→2025→Agricultural Process Engineering→Engineering Properties of Agricultural Produce

Q6

MCQ[1 Mark]

The sphericity of a cylindrical potato sample having diameter of 1.0 cm and length of 5.0 cm is closest to:

(A)

0.98

(B)

0.31

(C)

0.17

(D)

0.55

Explanation

GATE→2023→Agricultural Process Engineering→Engineering Properties of Agricultural Produce

Q7

MSQ[1 Mark]

Identify the dimensionless parameter(s) from the following:

(A)

Cone index

(B)

Puddling index

(C)

Performance index

(D)

Reel index

Explanation

GATE→2022→Agricultural Process Engineering→Engineering Properties of Agricultural Produce

Q8

NAT[1 Mark]

If the specific heat capacity ($c_{p}$) of solids in potato is 837.36 $\text{J }\text{kg}^{-1}\text{K}^{-1}$, then the specific heat capacity of potatoes in $\text{J }\text{kg}^{-1}\text{K}^{-1}$ with 85% moisture content (wet basis) is [round off to two decimal places]

Explanation

Evaporation and Drying

15 Questions

GATE→2026→Agricultural Process Engineering→Evaporation and Drying

Q9

NAT[1 Mark]

At an initial pressure of 100 kPa, 1 kg air is compressed reversibly from 15 litres to 1 litre at final pressure of 2000 kPa. Neglecting other losses, the Polytropic Exponent (n) is ________. (Rounded off to three decimal places)

Explanation

GATE→2026→Agricultural Process Engineering→Evaporation and Drying

Q10

MCQ[2 Marks]

A single effect evaporator is used to concentrate orange fruit juice with 2.7:1 concentration ratio of product solid to feed solid. The juice is fed to the evaporator at 100 kg.h−1 and 30 °C, where the product moisture evaporates at 60 °C. The specific heat of juice is 3.9 kJ.kg−1.°C−1. The latent heat of vaporisation at 60 °C is 2450 kJ.kg−1. Heat to accomplish the evaporation, in MJ.h−1, is nearest to (A) 165.96 (B) 117.06 (C) 154.26 (D) 142.56

(A)

165.96

(B)

117.06

(C)

154.26

(D)

142.56

Explanation

GATE→2026→Agricultural Process Engineering→Evaporation and Drying

Q11

MCQ[2 Marks]

At 60 °C dry bulb temperature, saturated water vapour pressure is 20 kPa and relative humidity is 20%. The corresponding absolute humidity of air at atmospheric pressure is nearest to (Take molecular weight of water = 18.02 g.mol–1, molecular weight of air = 28.97 g.mol–1, and atmospheric pressure = 101.325 kPa) (A) 0.026 (B) 0.032 (C) 0.004 (D) 0.041

(A)

0.026

(B)

0.032

(C)

0.004

(D)

0.041

Explanation

GATE→2025→Agricultural Process Engineering→Evaporation and Drying

Q12

MCQ[1 Mark]

In rice milling, the rubber roll sheller is used for:

(A)

Separating paddy from brown rice

(B)

Removal of bran adhering to rice kernels

(C)

Separating husk layer from paddy grains

(D)

Removal of husk layer from white rice

Explanation

GATE→2025→Agricultural Process Engineering→Evaporation and Drying

Q13

NAT[1 Mark]

Apple slices are dried from a moisture content of 65% (dry basis) to 10% (dry basis) in a hybrid solar dryer under falling rate period. The apple slices have a drying rate constant of $\frac{1}{104}\text{ minute}^{-1}$. Considering an equilibrium moisture content of 2% (dry basis), the time required for drying is ___ minutes. (Rounded off to 2 decimal places)

Explanation

GATE→2025→Agricultural Process Engineering→Evaporation and Drying

Q14

NAT[1 Mark]

The quantity of water needed to increase the moisture content of 50 kg paddy grains from 13% (dry basis) to 35% (dry basis) in the hydrothermal treatment process is ___ kg. (Rounded off to 2 decimal places)

Explanation

GATE→2025→Agricultural Process Engineering→Evaporation and Drying

Q15

MSQ[2 Marks]

Match the following psychrometric processes (Column I) with the respective changes in thermodynamic properties (Column II) of air-water vapor mixture: Column I: 1. Sensible cooling 2. Cooling and dehumidification 3. Chemical dehumidification 4. Heating and humidification Column II: P. DBT increases and DPT decreases Q. DBT increases and DPT increases R. DBT decreases and DPT remains constant S. DBT decreases and DPT decreases

(A)

1-R, 2-S, 3-Q, 4-P

(B)

1-P, 2-R, 3-S, 4-Q

(C)

1-R, 2-S, 3-P, 4-Q

(D)

1-P, 2-Q, 3-S, 4-R

Explanation

GATE→2024→Agricultural Process Engineering→Evaporation and Drying

Q16

MSQ[1 Mark]

Incorrect statement(s) with respect to hydrothermal treatment of paddy is/are:

(A)

Process imparts hard texture to grain

(B)

Retention of Vitamin B is less

(C)

Cooking to the same degree of softness requires less time

(D)

Bran obtained contains higher oil content

Explanation

GATE→2024→Agricultural Process Engineering→Evaporation and Drying

Q17

MSQ[1 Mark]

Falling rate period of drying can be explained by one/more of the following:

(A)

Capillary rise of water

(B)

Molecular diffusion of water

(C)

Surface cooling

(D)

Surface evaporation

Explanation

GATE→2024→Agricultural Process Engineering→Evaporation and Drying

Q18

NAT[1 Mark]

A single effect evaporator concentrates $9090\text{ kg}\cdot\text{h}^{-1}$ herbal extract of 12% solids entering at 300 K to a final solid concentration of 20%. Assuming negligible product loss through vapor, the amount of concentrated product, in kg, is ___ (Answer in integer)

Explanation

GATE→2023→Agricultural Process Engineering→Evaporation and Drying

Q19

MSQ[2 Marks]

The percentage absolute humidity of air becomes equal to the percentage relative humidity, when

(A)

absolute humidity of air is relative humidity

(B)

saturated humidity of air is equal to relative humidity

(C)

air is almost or completely dry

(D)

air is almost or completely saturated

Explanation

GATE→2022→Agricultural Process Engineering→Evaporation and Drying

Q20

NAT[1 Mark]

In a triple effect feed forward evaporator, pineapple juice is entering at the rate of $6.3\text{ kg }\text{s}^{-1}$ and leaving the last effect as 50% concentrate. The system is using saturated steam of $2.48\text{ kg }\text{s}^{-1}$ at $121.1^{\circ}C$. If vapour transferred from the first to the second effect, second to third effect and third to ambient are 5675, 6053 and 6416 $\text{kg }\text{h}^{-1}$, respectively, the steam economy of the evaporator is [round off to two decimal places]

Explanation

GATE→2022→Agricultural Process Engineering→Evaporation and Drying

Q21

NAT[1 Mark]

If an osmo-dehydrated fruit slice has 72% moisture content on wet basis, the moisture content of the same fruit slice on dry basis in per cent is [round off to one decimal place]

Explanation

GATE→2022→Agricultural Process Engineering→Evaporation and Drying

Q22

MCQ[2 Marks]

The water activity of potato is 0.942. As per Raoult's law, the most efficient solution for osmotic dehydration of potato is (Molar mass of sucrose $=342\text{ g mole}^{-1}$, and $\text{NaCl}=58.5\text{ g mole}^{-1}$)

(A)

20% sucrose solution

(B)

20% NaCl solution

(C)

10% sucrose solution + 10% NaCl solution

(D)

15% sucrose solution + 5% NaCl solution

Explanation

GATE→2022→Agricultural Process Engineering→Evaporation and Drying

Q23

NAT[2 Marks]

Parboiled paddy is to be dried in a tray dryer under steady state conditions from an initial free moisture content of $0.40\text{ kg H}_{2}\text{O }(\text{kg dry solid})^{-1}$ to final free moisture content of $0.02\text{ kg H}_{2}\text{O }(\text{kg dry solid})^{-1}$. The dry solid mass is 99.8 kg and the top surface area for drying is $4.654\text{ m}^{2}$. The drying is occurring in both constant and falling rate periods. If constant drying rate of $1.51\text{ kg H}_{2}\text{O m}^{-2}\text{h}^{-1}$ is followed up to a critical moisture content of $0.195\text{ kg H}_{2}\text{O }(\text{kg dry solid})^{-1}$, then the total drying time in hour will be [round off to two decimal places]

Explanation

Size Reduction and Material Handling

15 Questions

GATE→2025→Agricultural Process Engineering→Size Reduction and Material Handling

Q24

NAT[1 Mark]

Considering acceleration due to gravity as $9.81\text{ m}\cdot\text{s}^{-2}$ and $\pi$ as 3.14, the critical speed of a ball mill having 3600 mm mill diameter and 160 mm ball diameter is ___ rpm. (Answer in integer)

Explanation

GATE→2025→Agricultural Process Engineering→Size Reduction and Material Handling

Q25

NAT[2 Marks]

Locust beans having average particle diameter of 7 mm are ground at a rate of $10\text{ ton}\cdot\text{h}^{-1}$ to produce average particle diameter of 0.62 mm. The mill consumes 6.7 kW power at the given rate. For the same rate of grinding, using Rittinger's law, the power required to grind the beans to an average particle diameter of 0.25 mm is ___ kW. (Rounded off to 2 decimal places)

Explanation

GATE→2025→Agricultural Process Engineering→Size Reduction and Material Handling

Q26

NAT[2 Marks]

Apple juice $(\text{viscosity}=1.6\text{ cP})$ is being filtered through $2\text{ m}^{2}$ filter under a constant pressure. The juice has solid concentration of $0.04\text{ g}\cdot\text{mL}^{-1}$ in filtrate. The total pressure drop is 325.33 kPa. The values of cake and filter medium resistance are $1.85\times10^{11}\text{ m}\cdot\text{kg}^{-1}$ and $3.50\times10^{11}\text{ m}^{-1}$, respectively. The time required to filter 800 litres of juice is ___ hour. (Answer in integer)

Explanation

GATE→2024→Agricultural Process Engineering→Size Reduction and Material Handling

Q27

NAT[1 Mark]

An indented cylinder type rice grader has been fed with milled rice containing 18% brokens. After separation, head rice stream contains 3% brokens and the broken stream carried away 4% head rice. The effectiveness of the given rice grader on the basis of head rice separation, in fraction, is ___ (Rounded off to 3 decimal places)

Explanation

GATE→2024→Agricultural Process Engineering→Size Reduction and Material Handling

Q28

MCQ[2 Marks]

A power operated chaff cutter has an effective throat width of 450 mm and operating clearance of 150 mm. It is used for chopping straw at a moisture content of 20% with bulk density of $60\text{ kg}\cdot\text{m}^{-3}$ while passing through the feed rolls. The number of knives on the cutter head are 4, speed of the cutter head is 540 rpm and the theoretical length of cut is 10 mm. The theoretical capacity of the chaff cutter, in $\text{ton}\cdot\text{h}^{-1}$, is (Rounded off to 2 decimal places)

(A)

1.31

(B)

5.25

(C)

7.54

(D)

9.61

Explanation

GATE→2024→Agricultural Process Engineering→Size Reduction and Material Handling

Q29

MCQ[2 Marks]

Match the following types of mill in Column I based on their grinding mechanisms in Column II. Column I: P. Attrition mill, Q. Ball mill, R. Hammer mill, S. Roller mill Column II: 1. Compression and shear, 2. Impact and abrasion, 3. Crushing and shear, 4. Impact and shear

(A)

P-3; Q-2; R-4; S-1

(B)

P-2; Q-3; R-4; S-1

(C)

P-3; Q-1; R-4; S-2

(D)

P-3; Q-4; R-1; S-2

Explanation

GATE→2024→Agricultural Process Engineering→Size Reduction and Material Handling

Q30

NAT[2 Marks]

Sorghum flour obtained from a grinder was analyzed by IS sieves for particle size determination. The data obtained are as follows: IS sieve number: 100, 70, 50, 40, 30, 20, PAN Mass of flour retained (g): 10.1, 16.5, 36.2, 82.8, 95.0, 9.4 (Note: Check corresponding sieve aperture sizes) The average particle size of the flour, in mm, is ___ (Rounded off to 3 decimal places)

Explanation

GATE→2023→Agricultural Process Engineering→Size Reduction and Material Handling

Q31

MCQ[1 Mark]

If the diameter of fat globule in a cream separator is reduced to half and the rotational speed of the centrifuge increased to three times, the terminal settling velocity of fat globule is

(A)

decreased to 0.44 times

(B)

increased to 0.44 times

(C)

decreased to 2.25 times

(D)

increased to 2.25 times

Explanation

GATE→2023→Agricultural Process Engineering→Size Reduction and Material Handling

Q32

NAT[1 Mark]

The minimum fluidization height of 1.20 m is maintained during fluidized bed drying of carrots. The bed diameter of the fluidized bed dryer is 0.6 m. If mass and solid density of carrots are 250 kg and $1040\text{ kg}\text{ m}^{-3}$ respectively, then the porosity of the bed at the minimum fluidization condition is ___ (rounded off to 3 decimal places, Consider $\pi=3.14$).

Explanation

GATE→2023→Agricultural Process Engineering→Size Reduction and Material Handling

Q33

NAT[1 Mark]

The lighter liquid layer and the interphase layer in a basket centrifuge, rotating at a speed of 1000 rpm, are 0.1025 m and 0.105 m away from the center, respectively. Considering the densities of lighter and heavier liquids as 920 kg $\text{m}^{-3}$ and $1015\text{ kg}\text{ m}^{-3}$, the differential pressure in horizontal direction required to maintain the interphase layer in kPa is ___ (rounded off to 3 decimal places, Consider $\pi=3.14$).

Explanation

GATE→2023→Agricultural Process Engineering→Size Reduction and Material Handling

Q34

NAT[1 Mark]

The upstream and downstream pressures in a homogenizer during homogenization of milk are maintained at 250 bar and 10 bar, respectively. If density of milk is $1030\text{ kg}\text{ m}^{-3}$, then the velocity at which milk comes out of the homogenizing valve in m $\text{S}^{-1}$ is ___ (rounded off to 3 decimal places).

Explanation

GATE→2023→Agricultural Process Engineering→Size Reduction and Material Handling

Q35

MCQ[2 Marks]

In a juice filtration process, solid concentration per $\text{m}^{3}$ of filtrate is 0.2 kg. During filtration of $12.49\text{ m}^{3}$ of juice, 0.02 m thick cake (porosity of 0.32) is deposited. If 2.5 kg of solid is collected in 180 s, the pressure drop across the cake in kPa is [Absolute viscosity of juice is $2.12\times10^{-3}\text{ kg}\text{ m}^{-1}\text{s}^{-1}$, and specific cake resistance is $1.2\text{ x }10^{8}\text{ m kg}$]

(A)

0.18

(B)

1.81

(C)

18.06

(D)

180.60

Explanation

GATE→2022→Agricultural Process Engineering→Size Reduction and Material Handling

Q36

MCQ[1 Mark]

Energy requirement (E) to produce a change (dX) in dimension X of a particular size can be expressed as $\frac{dE}{dx}=-\frac{c}{x^{n}}$ where, c is constant and n according to Rittinger's law is

(A)

\frac{1}{2}

(B)

\sqrt{2}

(C)

\frac{3}{2}

(D)

2

Explanation

GATE→2022→Agricultural Process Engineering→Size Reduction and Material Handling

Q37

MCQ[2 Marks]

The mass fraction retained on the $i^{th}$ sieve is $x_i$ and $\overline{D_{p_{l}}}$ is the average opening size of $i^{th}$ and $(i-1)^{th}$ sieves. The volume surface mean diameter $(\overline{D_{S}})$ of particles retained on n number of sieves is

(A)

\overline{D_{s}}=\frac{1}{\Sigma_{i=1}^{n}(\frac{x_{i}}{D_{pi}})}

(B)

\overline{D_{S}}=\sum_{i=1}^{n}x_{i}\overline{D_{p_{l}}}

(C)

\overline{D}_{s}=|\frac{1}{\sum_{i=1}^{n}(\frac{x_{i}}{D_{pi}})}|^{1/3}

(D)

\overline{D}_{s}=|\frac{1}{\sum_{i=1}^{n}(\frac{x_{i}}{D_{pi}})}|^{2/3}

Explanation

GATE→2022→Agricultural Process Engineering→Size Reduction and Material Handling

Q38

NAT[2 Marks]

Sweet sorghum with an initial average particle size of 4.0 mm was pulverized using a burr mill at two different gap settings between stones. The average feed rate of the material is $200\text{ kg }\text{h}^{-1}$. The resultant flour was analyzed by IS sieves for particle size determination and was found to be 0.336 mm and 0.306 mm for the first and second gap settings, respectively. Using Kick's law, if the power required to grind the sorghum at first setting is 7.2 kW, the power requirement in kW with the second [round off to two decimal places] setting is

Explanation

Processing of Agriculture Produce

1 Question

GATE→2022→Agricultural Process Engineering→Processing of Agriculture Produce

Q39

MCQ[2 Marks]

Match the following reactants in Column I with the most appropriate purpose used in processing as mentioned in Column II Column I: I. Vitamin E II. Calcium salts III. Edible waxes IV. Methyl Bromide Column II: P. fumigant for insect killing Q. reduces shrinkage losses R. antioxidant with vitamin A in oils S. firming agent in fruits

(A)

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

(B)

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

(C)

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

(D)

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

Explanation

Storage Systems

4 Questions

GATE→2026→Agricultural Process Engineering→Storage Systems

Q40

MCQ[1 Mark]

A circular mild steel storage bin of 8 m height contains wheat having bulk density of 800 kg.m−3. The coefficient of static friction between wheat grain and bin wall is 0.40 and hydraulic radius of the bin is 1 m. Equivalent diameter of the bin, in m, is (A) 4 (B) 8 (C) 1 (D) 2

(A)

4

(B)

8

(C)

1

(D)

2

Explanation

GATE→2025→Agricultural Process Engineering→Storage Systems

Q41

NAT[2 Marks]

A cylindrical concrete silo of 6 m internal diameter and 24 m height is filled with rough rice having bulk density of $635\text{ kg}\cdot\text{m}^{-3}$. The angle of friction between concrete wall and rough rice is $30^{\circ}$. The ratio between lateral and vertical pressure is 0.4. The ratio of lateral pressure at 10 m depth to the 5 m depth is ___ (Rounded off to 2 decimal places)

Explanation

GATE→2023→Agricultural Process Engineering→Storage Systems

Q42

MCQ[2 Marks]

Cheese is packed in a bilayer plastic package made up of low density polyethylene (LDPE) and polyethylene terephthalate (PET). The thickness of LDPE and PET in the package are 1.5 mm and 1.3 mm, respectively. The surface area of the plastic package is $6.25\text{ cm}^{2}$. The partial pressure difference of oxygen across the package wall is 0.30 atm. The permeability coefficient of oxygen in LDPE and PET are $4.18\times10^{-8}\text{ cm}^{3}\text{ cm cm}^{-2}\text{s}^{-1}\text{atm}^{-1}$ and $1.67\times10^{-10}\text{ cm}^{3}\text{ cm cm}^{-2}\text{s}^{-1}\text{atm}^{-1}$, respectively. If the food gets spoiled when it absorbs 0.025 ml of oxygen, then the shelf life of food in days is

(A)

121

(B)

103

(C)

73

(D)

61

Explanation

GATE→2022→Agricultural Process Engineering→Storage Systems

Q43

NAT[2 Marks]

A cylindrical metallic silo of 3 m internal diameter and 10 m depth is loaded with maize grain having bulk density of $720\text{ kg }\text{m}^{-3}$. The angle of internal friction between the maize grains is $24^{\circ}$, and that between the grain and wall is $22^{\circ}$. Using Airy's theory, the calculated lateral pressure in kPa at the bottom of the silo is [round off to two decimal place] (Take $g=9.81\text{ ms}^{-2}$)

Explanation