Q. A 220 V DC shunt motor takes 3 A at no-load. It draws 25 A when running at full-load at 1500 rpm. The armature and shunt resistances are 0.5 Ω and 220 Ω, respectively. The no- load speed in rpm (round off to two decimal places) is                                       . Solution:

Q. A single-phase transformer of rating 25 kVA, supplies a 12 kW load at power factor of 0.6 lagging. The additional load at unity power factor in kW (round off to two decimal places) that may be added before this transformer exceeds its rated kVA is                     . Solution:

Q. The magnetic circuit shown below has uniform cross-sectional area and air gap of 0.2 cm. The mean path length of the core is 40 cm. Assume that leakage and fringing fluxes are negligible. When the core relative permeability is assumed to be infinite, the magnetic flux density computed in the air gap is 1

Q. The voltage across and the current through a load are expressed as follows The average power in watts (round off to one decimal place) consumed by the load is Solution:

Q. A 0.1 µF capacitor charged to 100 V is discharged through a 1 kΩ resistor. The time in ms (round off to two decimal places) required for the voltage across the capacitor to drop to 1 V is _______ Solution:

Q. The probability of a resistor being defective is 0.02. There are 50 such resistors in a circuit. The probability of two or more defective resistors in the circuit (round off to two decimal places) is     . Solution: Probability of a resistor being defective (P) = 0.02 Number of resistors (n) = 50 Mean (λ)

Q. If 𝐀 = 2𝑥𝐢 + 3𝑦𝐣 + 4𝑧𝐤   and 𝑢 = 𝑥2 + 𝑦2 + 𝑧2, then div(𝑢𝐀) at (1, 1, 1) is Ans: 45 Solution:

Q. The line currents of a three-phase four wire system are square waves with amplitude of 100 A. These three currents are phase shifted by 120° with respect to each other. The rms value of neutral current is A. 0 A B. 100 A C. 3 A D. 1 A Ans: 100 A Solution: