TNPSC Engineering Services Previous Year Paper 2008 Engineering and Instrumentation
| TNPSC – Combined – Engg. – Services – 2008 – Electrical & Instrumentation | |
| Sr. No. | Questions with multiple options |
| 1. | With the increase in temperature, the resistance of the pure metals
(a) Increases (b) Decreases (c) First increases and then decreases (d) Remains constant |
| 2. | Which of the following statements is false in case of a series circuit?
(a) The voltage drop across each resistance is the same (b) The current flowing through each resistance is the same (c) Applied voltage is equal to the sum of the voltage drops across individual resistors (d) Resistors are additive |
| 3. | Two alternating quantities are added.
(a) Arithmetically (b) Graphically (c) Vectorially (d) Geometrically |
| 4. | All the rules and laws which apply to dc networks also apply to ac networks consisting of
(a) Resistance only (b) Inductance only (c) Capacitance only (d) All of these |
| 5. | A capacitor
(a) Offers easy path to a.c. but blocks d.c. (b) Offers easy path to d.c. but blocks a.c. (c) Offers easy path to both a.c. and d.c. (d) Blocks a.c. |
| 6. | A unit impulse function is obtained on the differentiation of
(a) A unit ramp function (b) A unit step function (c) A unit triplet (d) A unit doublet |
| 7. | The equation for 25 cycles current sine wave having rms value of 30 amperes, will be
(a) 30 sin 25t (b) 30 sin 50t (c) 42.4 sin 25 (d) 42.4 sin 50πt |
| 8. | When a two-winding transformer is connected as an autotransformer. Its efficiency (full-load)
(a) Remains same (b) Increases (c) Decreases (d) Rises to 100% |
| 9. | During load-shedding
(a) System voltage is reduced (b) System frequency is reduced (c) Some loads are switched off (d) System power factor is changed |
| 10. | If the load on a dc shunt motor is increased, its speed decreases primarily due to
(a) Increase in its flux (b) Decrease in back emf (c) Increase in armature current (d) Decrease in brush drop |
| 11. | DC series motors are best suited for traction because
(a) Torque is proportional to the square of the armature current and speed is proportional to the torque. (b) Torque is proportional to the square of the armature current and speed is inversely proportional to the torque. (c) Torque and speed both are proportional to the square of the armature current. (d) None of these. |
| 12. | The impulse response of an R-L circuit is a
(a) Rising exponential function (b) Decaying exponential function (c) Step function (d) Parabolic function |
| 13. | The damping winding in a synchronous motor is generally used to
(a) Prevent hunting and provide the starting torque (b) Reduce eddy currents (c) Minimise vibrations (d) Reduce noise level |
| 14. | In a synchronous generator operating at zero pf lagging, the effect of armature reaction is
(a) Magnetizing (b) Demagnetizing (c) Cross-magnetizing (d) Both magnetizing and cross magnetizing |
| 15. | The disadvantage of starting an induction motor with a star-delta starter is that
(a) The starting torque is one-third of the torque in case of delta connection (b) During starting high losses result (c) The starting torque increases and the motor runs with jerks (d) None of these |
| 16. | The advantage of starting a slip-ring induction motor with the help of rotor resistance as compared to other methods is that the
(a) Starting torque increases due to rotor resistance (b) Starting current is reduced (c) Starter can be built directly into the rotor (d) None of these |
| 17. | Electrical machines are designed to have maximum efficiency at
(a) Full-load (b) 50% of full-load (c) Near about full-load (d) Mo-load |
| 18. | If the system has multiple pole on the w-axis, it is
(a) Stable (b) Marginally stable (c) Unstable (d) Conditionally stable |
| Published on 8th Oct 2021 | |
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