BCS Agriculture cadre — Agricultural Engineering (subject code 821)

Bangladesh · Bangladesh Public Service Commission · civil-service

256practice questions written to this syllabus
15subjects

Format

Preliminary 200-mark MCQ (2 h); written 900 marks; viva 200 marks. Code 821 is a 200-mark post-related paper.

Sections

Over the years

Preliminary marks were raised from 100 to 200 from the 35th BCS. Same core as GATE AG: machinery, irrigation and food engineering. Syllabus PDF (pp. 192–193): https://objectstorage.ap-dcc-gazipur-1.oraclecloud15.com/n/axvjbnqprylg/b/V2Ministry/o/office-bpsc/2024/12/36342dd1ff6e4c418894b0ae354c9c65.pdf

Official source: https://bpsc.gov.bd/pages/static-pages/691997b3933eb65569dde2bf

Subjects this exam draws on

Heat & Mass Transfer7 questionsMachine Design27 questionsFarm Machinery & Equipment I — Tillage, Sowing, Planting, Fertiliser13 questionsFarm Machinery & Equipment II — Plant Protection, Harvesting, Threshing15 questionsMechanics of Tillage & Traction (Soil Dynamics)15 questionsFarm Machinery Management & Economics6 questionsIrrigation Engineering (Soil-Water-Plant, Conveyance, Surface Methods)27 questionsSprinkler & Micro-Irrigation Systems45 questionsEngineering Properties of Agricultural Produce9 questionsPost-Harvest Engineering of Cereals, Pulses & Oilseeds13 questionsPost-Harvest Engineering of Horticultural Crops27 questionsFood & Dairy Engineering13 questionsRefrigeration, Air-Conditioning & Cold-Chain Engineering3 questionsStorage Engineering, Material Handling & Packaging22 questionsFood Quality, Safety & Process Plant Design14 questions

Five practice questions, worked

Original questions written to this exam's published syllabus and pattern. Not past papers.

1. A plane brick wall 0.2 m thick (k = 0.8 W/m·K) has an area of 10 m². Its faces are held at 35 °C and 5 °C. The steady heat flow through the wall is

  1. 1,200 W
  2. 120 W
  3. 12.0 W
  4. 48.0 W
Answer and working

A. 1,200 W

Q = kAΔT/L = 0.8 × 10 × 30 / 0.2 = 1,200 W. 120 W is the flux per square metre (W/m²) mistaken for the total; 12 W comes from entering the thickness as 20 cm instead of 0.2 m; 48 W comes from multiplying by L instead of dividing.

Heat & Mass Transfer · Steady conduction through plane walls and cylinders

2. Why is grey cast iron a common material for gearbox housings and machine beds but not for highly stressed tension members?

  1. It cannot be machined to close tolerances, so it is only used where no dimensional accuracy is needed
  2. It casts easily, damps vibration and is strong in compression, but it is brittle and weak in tension
  3. It is ductile and strong in tension but too expensive to machine
  4. It has a higher modulus of elasticity than steel, so it deflects less, but it rusts too quickly to be used in tension
Answer and working

B. It casts easily, damps vibration and is strong in compression, but it is brittle and weak in tension

Grey cast iron flows well into complex moulds, its graphite flakes damp vibration and give good machinability, and its compressive strength is several times its tensile strength. The same flakes make it brittle and weak in tension. Its modulus is lower than that of steel, not higher.

Machine Design · The design process, materials and factor of safety

3. A farmer ploughs a clay loam while it is very wet. What is the most likely result?

  1. A fine, friable tilth with low draft
  2. Better aggregate stability than tilling at friable moisture
  3. Smearing and compaction, with large hard clods after drying
  4. Less wheel slip and lower fuel use
Answer and working

C. Smearing and compaction, with large hard clods after drying

Wet soil deforms plastically: the tool smears and compacts it, and when it dries the slices set into hard clods. The friable range, between too wet and too dry, gives the best tilth for the least energy. Wet soil also increases wheel slip.

Farm Machinery & Equipment I — Tillage, Sowing, Planting, Fertiliser · Objectives and types of tillage

4. In a lever-operated knapsack sprayer, the air chamber (pressure chamber) is provided mainly to

  1. agitate the chemical in the tank
  2. filter the liquid before the nozzle
  3. increase the volume of the tank so more liquid can be carried per filling
  4. steady the nozzle pressure
Answer and working

D. steady the nozzle pressure

Each lever stroke delivers a pulse; the compressed air in the chamber stores energy and releases it between strokes so nozzle pressure stays nearly steady. Agitation and filtering are done by other parts.

Farm Machinery & Equipment II — Plant Protection, Harvesting, Threshing · Sprayers: hydraulic, air-assisted and electrostatic

5. In a disc harrow, why are the front gangs set at opposite angles?

  1. To increase the side draft for better soil inversion
  2. So that their side forces largely cancel
  3. To reduce the vertical load on the discs to roughly zero
  4. To allow the harrow to work without any draft
Answer and working

B. So that their side forces largely cancel

Each angled gang produces a side force; opposing gangs balance them so the harrow runs straight. Vertical load is still needed for penetration, and draft cannot be zero.

Mechanics of Tillage & Traction (Soil Dynamics) · Soil-tool mechanics

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