ICAR AIEEA-PG — Agricultural Engineering & Technology (Major Subject Group 10) · India · National Testing Agency for ICAR
Original practice questions written to the published syllabus · not past papersWhere the energy for farm work comes from, how much is available, and how mechanisation is measured.
In the exams: GATE AG Section 3 Sources of Power; ICAR AIEEA-PG Unit V; PRC ABE power and machinery (32%)
ICAR AIEEA-PG — Agricultural Engineering & Technology
Unit V farm machinery and power with renewable energy: characteristics of human, animal, mechanical and electrical sources, harness types, biogas plant types, gasifier types, biodiesel; Unit II electric motors: induction motor speed, slip, input and output power, starters.
How our questions for ICAR AIEEA-PG spread across the units of Farm Power Sources. Difficulty: 27 easy, 29 medium, 8 hard.
| Animal draught power and harnessing | 11 | |
| Electrical power on the farm | 11 | |
| Biomass and biofuels as power sources | 10 | |
| Mechanical power: engines and tractors | 8 | |
| Human power and its limits | 7 | |
| Solar power as a farm power source | 7 | |
| Wind power as a farm power source | 6 | |
| Farm power availability (kW/ha) | 4 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
When a worker does hard physical work, most of the metabolic energy released from food appears as:
B. Waste heat
Gross mechanical efficiency of human work is only about 20–25% at best, so roughly three-quarters or more of the metabolic energy becomes heat. This is why heat and humidity limit how long a person can work hard. That heat must be lost to the surroundings.
Which statement about human power output and duration is correct?
A. The power a person can sustain falls steeply as the duration of effort increases
A person can produce several hundred watts or more for seconds but only about 75 W or less all day. Output is not constant, peak exceeds sustained power, and heat above body-comfort levels reduces output.
A pair of bullocks exerts a steady pull of 1.2 kN while walking at 3 km/h. What power do they develop?
A. 1.00 kW
v = 3/3.6 = 0.833 m/s; P = 1.2 kN × 0.833 m/s = 1.00 kW. Multiplying by km/h without converting gives 3.60 kW, the commonest slip. 12.96 kW multiplies by 3.6 instead of dividing (1.2 × 3 × 3.6); 10.0 kW is a factor-of-ten slip.
An animal-drawn mouldboard plough cuts a furrow 20 cm wide and 12 cm deep in a soil with a specific draught of 4 N/cm². What is the draught?
B. 960 N
Draught = specific draught × furrow area = 4 N/cm² × (20 × 12) cm² = 960 N. The other options are decimal slips or half the area; always multiply width by depth in the same units as the specific draught.
Why do diesel (compression-ignition) engines, rather than petrol engines, power nearly all tractors?
A. Higher compression ratio gives higher thermal efficiency and good low-speed torque
Diesel engines use high compression ratios, giving higher thermal efficiency, and deliver high torque at low speed, suited to heavy continuous farm loads. They are heavier and slower-running than petrol engines and depend on fuel injection.
Which motor is the standard choice for farm pumps, threshers and grinders where a three-phase supply is available?
D. Three-phase squirrel-cage induction motor
The squirrel-cage induction motor is robust, cheap and nearly maintenance-free. DC series and universal motors are for traction and small hand tools; synchronous motors are for special constant-speed or power-factor duties.
At a hot, elevated site the air density is 1.10 kg/m³ instead of the standard 1.225 kg/m³. By how much is the power in the wind reduced at the same wind speed?
D. 10.2%
Power is proportional to density: 1.10/1.225 = 0.8980, a reduction of 10.2%. Cubing the density ratio applies the speed rule to density (27.6%); 11.4% uses the wrong base. 19.4% squares the density ratio (1 − 0.898²).
A farm has 8 cattle each giving 10 kg of fresh dung per day. Taking a gas yield of 0.04 m³ per kg of fresh dung, what daily biogas production can be expected?
C. 3.2 m³/day
Dung = 8 × 10 = 80 kg/day; gas = 80 × 0.04 = 3.2 m³/day. 0.4 m³ is for one animal only. 0.32 and 32 m³/day are factor-of-ten slips.
The same 80 kg/day of dung is mixed 1:1 with water (slurry density about 1000 kg/m³). For a hydraulic retention time of 40 days, what digester volume is needed?
B. 6.4 m³
Slurry = 80 + 80 = 160 kg/day ≈ 0.16 m³/day; volume = 0.16 × 40 = 6.4 m³. Forgetting the water gives 3.2 m³; 0.16 m³ is one day's feed only. 64 m³ is a factor-of-ten slip.
A block has 400 ha net sown area, 25 tractors of 30 kW, 10 power tillers of 9 kW, 150 electric motors of 5 kW, 60 diesel engines of 4 kW, 300 draught animals (0.38 kW each) and 900 workers (0.05 kW each). What is the farm power availability?
B. 4.97 kW/ha
Total = 750 + 90 + 750 + 240 + 114 + 45 = 1,989 kW; ÷ 400 ha = 4.97 kW/ha. Excluding people and animals gives 4.58; counting tractors only gives 1.88; dividing by a gross cropped area of 700 ha gives 2.84.
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