Q. If 𝑓 = 2𝑥3 + 3𝑦2 + 4𝑧, the value of line integral ∫𝐶 grad𝑓 ∙ 𝑑𝐫 evaluated over contour C formed by the segments (-3, -3, 2)→(2, -3, 2) →(2, 6, 2) →(2, 6, -1) is Ans:

Q. A current controlled current source (CCCS) has an input impedance of 10 Ω and output impedance of 100 kΩ. When this CCCS is used in a negative feedback closed loop with a loop gain of 9, the closed loop output impedance is (A) 10 Ω (B) 100 Ω (C) 100 kΩ (D) 1000 kΩ

Q. Given, 𝑉𝑔𝑠 is the gate-source voltage, 𝑉𝑑𝑠 is the drain source voltage, and 𝑉𝑡ℎ is the threshold voltage of an enhancement type NMOS transistor, the conditions for transistor to be biased in saturation are (A) 𝑉𝑔𝑠 < 𝑉𝑡ℎ ; 𝑉𝑑𝑠 ≥ 𝑉𝑔𝑠 − 𝑉𝑡ℎ (B) 𝑉𝑔𝑠 > 𝑉𝑡ℎ ; 𝑉𝑑𝑠 ≥ 𝑉𝑔𝑠 − 𝑉𝑡ℎ

Q. The characteristic equation of a linear time-invariant (LTI) system is given by ∆(𝑠) = 𝑠4 + 3𝑠3 + 3𝑠2 + 𝑠 + 𝑘 = 0. The system is BIBO stable if Ans: Option (C) Solution:

Q. A three-phase synchronous motor draws 200 A from the line at unity power factor at rated load. Considering the same line voltage and load, the line current at a power factor of 0.5 leading is (A) 100 A (B) 200 A (C) 300 A (D) 400 A Ans: 400 A

Q. The parameter of an equivalent circuit of a three-phase induction motor affected by reducing the rms value of the supply voltage at the rated frequency is (A) rotor resistance (B) rotor leakage reactance (C) magnetizing reactance (D) stator resistance Ans: magnetizing reactance Solution: Magnetic reactance (Xm) is depends on airgap flux and the flux

Q. A six-pulse thyristor bridge rectifier is connected to a balanced three-phase, 50 Hz AC source. Assuming that the DC output current of the rectifier is constant, the lowest harmonic component in the AC input current is (A) 100 Hz (B) 150 Hz (C) 250 Hz (D) 300 Hz Ans: 250 Hz Solution: In a

Q. A 5 kVA, 50 V/100 V, single-phase transformer has a secondary terminal voltage of 95 V when loaded. The regulation of the transformer is (A) 4.5% (B) 9% (C) 5% (D) 1% Ans: 5% Solution: Voltage regulation is the change in secondary terminal voltage from no load to full load at a specific power

Q. The symbols, 𝑎 and 𝑇, represent positive quantities, and 𝑢(𝑡) is the unit step function. Which one of the following impulse responses is NOT the output of a causal linear time-invariant system? (A) 𝑒+𝑎𝑡𝑢(𝑡) (B) 𝑒−𝑎(𝑡+𝑇)𝑢(𝑡) (C) 1 + 𝑒−𝑎𝑡𝑢(𝑡) (D) 𝑒−𝑎(𝑡−𝑇)𝑢(𝑡) Ans: 1 + 𝑒−𝑎𝑡𝑢(𝑡) Solution: a and T represents positive quantities.u(t) is

Q. Consider five people – Mita, Ganga, Rekha, Lakshmi and Sana. Ganga is taller than both Rekha and Lakshmi. Lakshmi is taller than Sana. Mita is taller than Ganga. Which of the following conclusions are true? (A) 1 and 3 (B) 3 only (C) 2 and 4 (D) 1 only Ans: 2 and 4 Solution: