ASRB NET — Farm Machinery & Power / Land & Water Management Engineering / Agricultural Structures & Process Engineering · India · Agricultural Scientists Recruitment Board (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%)
ASRB NET — Farm Machinery & Power
Farm power scenario, draught animal power and harnessing, mechanisation indices and energy analysis; theory-heavy MCQs.
How our questions for ASRB NET spread across the units of Farm Power Sources. Difficulty: 7 easy, 18 medium, 12 hard.
| Mechanisation indices | 12 | |
| Farm power availability (kW/ha) | 9 | |
| Biomass and biofuels as power sources | 4 | |
| Animal draught power and harnessing | 3 | |
| Mechanical power: engines and tractors | 3 | |
| Electrical power on the farm | 3 | |
| Human power and its limits | 2 | |
| Wind power as a farm power source | 1 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
In an energy audit, male labour is counted at 1.96 MJ per man-hour. What energy input is recorded for 12 men working 8 hours each?
D. 188.16 MJ
Man-hours = 12 × 8 = 96; energy = 96 × 1.96 = 188.16 MJ. 15.68 MJ counts only one worker; 23.52 MJ forgets the hours; 52.3 is the same energy in kWh, wrongly labelled MJ.
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.
Why are multi-blade, high-solidity rotors used on windmills that drive piston pumps for stock water?
A. High starting torque at low wind speed and slow rotation suit a pump that starts under load
High solidity gives high torque at low speed (tip speed ratio about 1), which a reciprocating pump needs to start. Two- or three-blade low-solidity rotors run at high tip speed ratios and suit generators.
Producer gas from an air-blown biomass gasifier has a low calorific value (roughly 4–6 MJ/m³) mainly because:
D. It contains a large fraction of nitrogen from the gasifying air
The combustible components are CO and H2 with some CH4, but air brings in nitrogen, which dilutes the gas along with CO2. Oxygen- or steam-blown gasifiers give richer gas.
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.
A district of 10,000 ha net sown area has 2.0 kW/ha. The target is 4.0 kW/ha, to be met entirely with 35 kW tractors. About how many additional tractors are needed?
D. 572 tractors
Additional power = (4.0 − 2.0) × 10,000 = 20,000 kW; tractors = 20,000/35 = 571.4 → 572. Using the full 4 kW/ha ignores existing power (1143). In practice targets are met with a mix of sources. 58 uses 350 kW per tractor, a factor-of-ten slip (20,000/350 = 57.1); 1715 adds the existing 2.0 kW/ha to the target (60,000/35).
Custom hiring centres (machinery banks) mainly raise the farm power effectively available to smallholders by:
C. Letting many farmers use machines they could not justify owning, when they need them
Hiring spreads fixed costs over more farms and hours, improving access and timeliness without each farmer buying a machine. It does not change machine ratings.
Two reports give very different 'levels of mechanisation' for the same state. What should you check first?
D. The definition used (power share, operation-wise area, energy share or stock) and the area and data year
There is no single agreed index: power-based, operation-based, energy-based and stock-based measures can differ widely. Compare like with like on definition, area basis and year before judging.
Operation-wise mechanisation data show tillage and threshing almost fully mechanised, but rice transplanting and cotton picking largely manual. What use is this for policy?
C. It identifies the operations where research, machinery development and subsidy will do most to raise the overall level
An overall index hides gaps. Operation-wise figures show bottlenecks such as transplanting and harvesting where targeted interventions pay off.
Ten here, 37 in the app. The Laisha app has every practice question we have written to ASRB NET in this subject, marked as you go, with timed papers, a jump-to-unanswered list and a certificate when you pass at 70 per cent.
Free for ten days, then one subscription of US$10 a month. We would rather say so here than have you find it later.
An AI operating system for agriculture: free guides, manuals and tools written for every country.