UPHESC Assistant Professor Agricultural Engineering PYQs

Concept: In the forced-feed (pressure) lubrication of tractor engines, the gear pump delivers oil at about 2–4 kg/cm², typically about 3 kg/cm².

1. A pressure-relief valve limits any excess.
2. Oil reaches the main and big-end bearings and the camshaft through drilled passages.

Short trick: Engine oil pressure ≈ 3 kg/cm² (≈ 40 psi).

Concept: Diesel knock is caused by a long ignition delay: fuel collects and then burns all at once.

1. Reduce the delay period by using high-cetane fuel.
2. Raise the compression ratio, which gives a higher air temperature.
3. Raise the inlet air pressure (supercharging). All three help.

Short trick: In CI, what causes SI knock cures CI knock (high CR, high pressure).

Concept: The engine gives nearly constant torque; the gearbox (transmission) changes the gear ratio to vary the torque at the driving wheels to suit the load.

1. Low gear → high torque for starting or climbing; high gear → low torque, high speed.
2. It cannot vary power (power is fixed by the engine); steering takes turns.

Short trick: Gearbox = torque converter for the road wheels.

Concept: In an epicyclic (planetary) gear train, some gear axes (the planets) revolve about a fixed axis (the sun gear) on an arm.

1. Simple, compound and reverted trains all have fixed axes.
2. Epicyclic trains are used in tractor final drives, differentials and automatic gearboxes.

Short trick: Epi-cycle = gear moving on a circle = planet gears.

Concept: Remote sensing rests on EM energy, the EM spectrum, energy interaction with the atmosphere and energy interaction with earth-surface features.

1. The satellite only carries the sensor that records reflected or emitted energy; there is no 'interaction with the satellite'.

Short trick: Energy interacts with atmosphere and target, not with the platform.

Concept: Agricultural drones serve precision farming in many ways.

1. Field mapping and crop-health (NDVI) imaging.
2. Precise spraying of pesticides and nutrients (Kisan drones).
3. Monitoring livestock, irrigation and water stress.

Short trick: Drone = eye + sprayer + watchman → all of these.

Concept: A synoptic view means that one image covers a very large area at the same moment.

1. It allows regional study of crops, floods and land use at one time.
2. Repetitive coverage and access to inaccessible areas are other advantages.

Short trick: Synoptic = 'see together' – big area, one shot.

Concept: Vector (points, lines, polygons) and grid/raster (cells) are the two basic ways of geo-coding spatial data, and are called the GIS data structures.

1. Vector gives precise boundaries and smaller files.
2. Grid (raster) suits continuous surfaces and imagery and makes overlay simple.
3. Ground truth is field verification and is not a coding system.

Short trick: Vector & grid = two GIS data structures.

Concept: Hardware means the physical parts; software means programs.

1. CPU, ALU (part of the CPU) and scanner are hardware.
2. Windows is an operating system, i.e. software.

Short trick: If you can touch it – hardware; Windows you install – software.

Concept: DRONE is commonly expanded as Dynamic Remotely Operated Navigation Equipment.

1. Technically it is a UAV (Unmanned Aerial Vehicle) or RPAS.
2. India's Drone Rules 2021 regulate their use, including Kisan drones.

Short trick: D-R-O-N-E: Dynamic Remotely Operated Navigation Equipment.