ICAR AIEEA PG Agriculture Engineering 14 July 2023 (Shift 1) Paper

Computers directly execute and understand only machine language (binary code consisting of $0$s and $1$s). All high-level languages (C, BASIC) and assembly language require compilers or assemblers for translation. Option analysis: (A) Machine language is the only native language directly understood by CPU circuitry. (B) C language requires a compiler. (C) Assembly language requires an assembler. (D) BASIC requires an interpreter or compiler.

In India, standard low-voltage three-phase AC distribution voltage for industrial and agricultural electric motors is $415\text{ V}$ line-to-line at $50\text{ Hz}$ ($240\text{ V}$ phase-to-neutral). Option analysis: (A) $110\text{ V}$ is standard American single-phase residential voltage. (B) $220\text{ V}$ / $240\text{ V}$ is standard Indian single-phase voltage. (C) $415\text{ V}$ is standard Indian three-phase motor operating voltage. (D) $660\text{ V}$ is specialized mining/industrial voltage.

Statement (I) is true: power factor is the ratio of real power to apparent power ($\cos \phi = P/S$), reflecting current-voltage phase alignment, whereas efficiency is output power divided by input power. Statement (II) is true: inductive loads (such as motors) draw lagging reactive power where current lags voltage. Option analysis: (A) Both Statement (I) and Statement (II) are true. (B) Neither statement is false. (C) Statement (II) is true. (D) Statement (I) is true.

In an AC circuit power triangle, Apparent Power ($S$) is the phasor (vector) sum of Real (Active) Power ($P$) and Reactive Power ($Q$): $\vec{S} = P + jQ$, with magnitude $S = \sqrt{P^2 + Q^2}$. Option analysis: (A) Real Power and Reactive Power vector sum equals Apparent Power. (B) Inverts relationship. (C) Inverts relationship. (D) Sum is never zero for energized operating circuits.

Skin effect is the tendency of an alternating electric current (AC) to distribute non-uniformly within a conductor, with current density greatest near the conductor surface and decreasing exponentially with depth. Option analysis: (A) Skin effect is the exact physical name of this phenomenon. (B) Peltier effect refers to thermoelectric heating/cooling at a junction. (C) Fleming provided rules for magnetic deflection/induction. (D) Gauss relates to electric/magnetic flux divergence.