Quiz: Electrical Engineering 3 June 2020

Quiz: Electrical Engineering
Exam: UPSSSC JE
Topic: Instruments & Measurements

Each question carries 1 mark.
Negative marking: 1/4 mark
Time: 10 Minute

Q1. For controlling the vibration of the disc of an ac energy meter, damping torque is produced by
(a) eddy current
(b) chemical effect
(c) electrostatic effect
(d) magnetic effect

Q2. Creep error may occur in induction type energy meter due to
(a) incorrect position of brake magnet
(b) incorrect adjustment of position of shading band
(c) over voltage across voltage coil
(d) increase in temperature

Q3. Holes are drilled on the opposite sides of the disc of an induction type energy meter to
(a) avoid creep on no load
(b) balance the disc
(c) dissipate the energy due to eddy current
(d) increase the deflecting torque

Q4. Which of the following is the main cause of creeping in the induction type energy meter?
(a) friction compensation
(b) lag/lead compensation
(c) overload compensation
(d) braking torque producing system

Q5. In a single-phase induction type energy meter, the lag adjustment is done to ensure that
(a) current coil flux lags the applied voltage by 90°
(b) pressure coil flux lags the applied voltage by 90°
(c) pressure coil flux is in phase with the applied voltage.
(d) current coil flux lags the pressure coil flux by 90°

Q6. Which of the following method is used for the measurement of high resistance?
(a) Carey Foster’s bridge method
(b) substitution method
(c) loss of charge method
(d) Potentiometer method

Q7. The sensitivity of Wheatstone bridge depends upon
(a) galvanometer voltage sensitivity
(b) galvanometer resistance
(c) bridge supply voltage
(d) all of the above

Q8. Wagner’s earthing device is used in ac bridge for
(a) shielding the bridge elements
(b) eliminating the stray electrostatic field effect
(c) eliminating the effect of earth capacitance
(d) eliminating the effect of inter-component capacitances

Q9. What should be the main characteristic of the null detector in a bridge measurement?
(a) accuracy
(b) precision
(c) Sensitivity
(d) Resolution

Q10. The dielectric loss of capacitor can be measured by which of the following?
(a) Wien bridge
(b) Owen bridge
(c) Shearing bridge
(d) Maxwell bridge

Solutions

S1. Ans. (a)
Sol. Eddy current

S2. Ans. (c)
Sol. Overvoltage across voltage coil

S3. Ans. (a)
Sol. To avoid creep on no load.

S4. Ans. (a)
Sol. Friction compensation is the right option.

S5. Ans. (b)
Sol. pressure coil flux lags the applied voltage by 90°

S6. Ans. (c)
Sol. Loss of charge method is used to calculate high resistance.

S7. Ans. (d)
Sol. All factors are responsible for sensitivity of Galvanometer

S8. Ans. (c)
Sol. eliminating the effect of earth capacitance

S9. Ans. (d)
Sol. Resolution should be the main characteristic.

S10. Ans. (d)
Sol. Shearing bridge

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