Agricultural Engineering Gate 2021 Questions with Answer

Ques 40 GATE 2021

A ball mill of 200 cm diameter grinds solid materials while operating with 10 cm size balls. If the same ball mill is used for wet grinding, charged with 20 cm diameter balls, the change in the operating speed in rpm is [round off to 2 decimal places] (Take π = 3.14 and g = 9.81 m s⁻²)

Ques 41 GATE 2021

Rushton turbine having an impeller diameter of 20 cm and operating at a stirrer speed of 200 rpm is used in a mixing tank. If the tank receives air at a volumetric flow rate of 0.2 m³ min⁻¹, the non-dimensional Froude Number, NFr is [round off to 2 decimal places]

Ques 42 GATE 2021

Match the following hulling mechanism in column 1 with the corresponding machine in column 2
Column 1
P Shear and compression
Q Friction and abrasion
R Shear, compression and friction
S Impact, abrasion and friction
Column 2
1 Blade type emery scourer
2 Horizontal Gota machine
3 Rubber roll dehusker
4 Under runner disc sheller

Ques 43 GATE 2021

Match the correct items in column 1 with column 2
Column 1
P Pipe-in-pipe heat exchanger
Q Shell and tube heat exchanger
R 1-2 shell and tube heat exchanger
S Cross flow heat exchanger
Column 2
1 Cooling of air
2 Simultaneous co-current and counter current heat exchange
3 Large flow rate
4 Small heat exchange area

Ques 44 GATE 2021

A 30 µm thick membrane having 3 m² surface area is used to separate NaCl from a solution at steady state condition. The mass transfer coefficient of NaCl at the solution side is 1×10^-6 m s^-1 and that at the other side of the membrane is 3×10^-7 m s^-1. Concentration of NaCl in the solution is 0.03 g (100 mL)^-1 and, that on the other side of the membrane is assumed to be zero. Permeability of the membrane is 9×10^-6 m s^-1. The rate of removal of the NaCl by the membrane in g h^-1 is

Ques 45 GATE 2021

In a size reduction operation, the power required to crush 2 ton of feed material per hour is 7.2 kW. Eighty per cent of the feed and product material pass through 4.75 mm and 0.5 mm sieve openings, respectively. The work index of the material is

Ques 46 GATE 2021

Ques 47 GATE 2021

In the figure shown above, each inside square is formed by joining the midpoints of the sides of the next larger square. The area of the smallest square (shaded) as shown, in cm² is:

Ques 48 GATE 2021

Ques 49 GATE 2021

The most economical trapezoidal channel section with 1:1 (horizontal:vertical) side slope is designed to carry a maximum of 40 cm depth of water at its full capacity. If the bed slope of the channel is 1:2500 and the Manning's roughness coefficient of channel section is 0.01, the estimated discharge capacity of the channel in m³ s⁻¹ is [round off to 2 decimal places]

Ques 50 GATE 2021

Water is discharged from a tank through a rectangular orifice of width 1.5 m and height 1.2 m. The water level in the tank is 3.5 m above the top edge of the orifice. If the coefficient of discharge of this orifice is 0.62, the discharge through the orifice in m³ s⁻¹ is [round off to 2 decimal places] (Take acceleration due to gravity, g = 9.81 m s⁻²)

Ques 51 GATE 2021

Two fully penetrating wells are 1.4 km apart in a homogeneous confined aquifer. The difference in their piezometric levels is 4.0 m. The groundwater flow is at steady and unidirectional. If the aquifer has a hydraulic conductivity of 3.5 m day⁻¹ and effective porosity of 40%, the time taken for water to move from one well to the other in days is [in integer]

Ques 52 GATE 2021

In a field test of drip irrigation system having an application efficiency of 90%, the minimum, maximum and average flow rates are found to be 45 L h⁻¹, 65 L h⁻¹ and 50 L h⁻¹, respectively. The manufacturer's coefficient of variation of the emitter is 0.07. If there is one emitter per plant, the drip irrigation efficiency in percent is [round off to 2 decimal places]