1. 1) Formative time lag depends on the mechanism of the avalanche growth in gap. The formative time lag is
usually
a. Much shorter than the statistical time lag
b. Much greater than the statistical time lag
c. Equal to the statistical time lag
d. None of these
ANSWER: Much shorter than the statistical time lag
2) The statistical time lag depends upon the
a. Size of gap
b. Quantity of radiation that produces the primary electrons
c. Amount of pre-ionization preset gap
d. All of these
ANSWER: All of these
3) According to the Paschen’s Law, the breakdown voltage of a uniform field gap is
a. Directly proportional to the gas pressure and inversely proportional to the electrode gap
b. Inversely proportional to the gas pressure and directly proportional to the electrode gap
c. Directly proportional to the both electrode gap and gas pressure
d. Inversely proportional to the both electrode gap and gas pressure
ANSWER: Directly proportional to the both electrode gap and gas pressure
4) For the high voltage conductors at high pressures, if the voltage is positive then the corona appears as a
a. Uniform bluish white sheath
b. Reddish glowing spots
c. Uniform greenish spots
d. None of these
ANSWER: Uniform bluish white sheath
2. 5) Field in case of rod gaps and sphere gaps are
a. Uniform, uniform
b. Uniform, non-uniform
c. Non-uniform, uniform
d. Non-uniform, non-uniform
ANSWER: Non-uniform, uniform
6) In Breakdown tests, the tests voltages required for these tests are usually of the order of
a. 0 – 10 kV
b. 20 – 50 kV
c. 50 – 100 kV
d. 100 – 200 kV
ANSWER: 50 – 100 kV
7) The increase in liquid hydrostatic pressure
a. Increases the breakdown strength
b. Decreases the breakdown strength
c. Does not affect the breakdown strength
d. None of these
ANSWER: Increases the breakdown strength
3. 8) In case of solid particles present in the liquid and in case of presence of only gas bubbles in liquids, the
direction of force is towards
a. Areas of maximum stress, areas of minimum stress
b. Areas of maximum stress, areas of maximum stress
c. Areas of minimum stress, areas of maximum stress
d. Areas of minimum stress, areas of minimum stress
ANSWER: Areas of maximum stress, areas of minimum stress
9) According to the Bubble theory, once a bubble is formed, it will elongate in the direction of electric field under
the influence of electrostatic forces. During elongation the volume of bubbles
a. Increases
b. Decreases
c. Remains constant
d. None of these
ANSWER: Remains constant
10) According to the Stressed Oil Volume theory, the breakdown strength is
a. Directly proportional to the stressed oil volume
b. Directly proportional to the square of the stressed oil volume
c. Inversely proportional to the stressed oil volume
d. None of these
ANSWER: Inversely proportional to the stressed oil volume
4. 11) Treeing phenomenon is observed in
a. Capacitors
b. Cables
c. Insulators
d. Only (a) and (b)
ANSWER: Only (a) and (b)
12) The liquid dielectrics contain voids or cavities within the medium or at the boundaries between the dielectric
and the electrodes. The electric field strength in the voids is
a. Lower than that across the dielectric
b. Higher than that across the dielectric
c. Equal to that across the dielectric
d. None of these
ANSWER: Higher than that across the dielectric
13) For very small cavities, discharge inception voltage
a. Decreases as the cavity depth increases
b. Increases as the cavity depth increases
c. Remains unaffected as the cavity depth increases
d. None of these
ANSWER: Decreases as the cavity depth increases
5. 14) Which among the following is not an example of impregnants?
a. Mineral oil
b. Chlorinated diphenyl
c. Vegetable oils
d. None of these
ANSWER: None of these
15) The example of artificial fibre is
a. Rayon
b. Cotton
c. Flax
d. Silk
ANSWER: Rayon
16) The most commonly used insulating materials for low and medium voltage cables is
a. Polyethylene
b. Porcelain
c. PVC
d. Vulcanized rubber
ANSWER: PVC
17) In paper based laminated construction, the typical value of dielectric constant and dielectric loss factor is
a. 3.5, 0.0015
b. 2.5, 0.0020
c. 3.5, 0.0025
d. 2.5, 0.0035
ANSWER: 3.5, 0.0025
6. 18) The resin bonded paper bushings are designed to operate at a maximum radial stress of
a. 5 kV/cm
b. 10 kV/cm
c. 15 kV/cm
d. 20 kV/cm
ANSWER: 20 kV/cm
19) Resins and varnishes are commonly used in
a. Generators and motors
b. Cables
c. Transformers
d. Circuit breakers
ANSWER: Generators and motors
20) The commonly used materials for HV insulation is
a. Paper-oil insulation
b. Polyester resin
c. Ceramic
d. PVC
ANSWER: Paper-oil insulation
21) The disadvantages of resonant transformers is
a. Pure sine wave output
b. No high power arcing
c. No repeated flashovers
d. Additional variable chokes
7. ANSWER: Additional variable chokes
22) In a series RLC circuit, the wave front and wave tail times are controlled by changing the value
a. R only
b. R and L simultaneously
c. R and C simultaneously
d. L and C simultaneously
ANSWER: R and L simultaneously
23) In a multistage impulse generator, for producing very high voltages, a bank of capacitors is
a. Charged in parallel and then discharged in series
b. Charged in series and then discharged in parallel
c. Charged in parallel and then discharged in parallel only
d. Charged in series and then discharged in series only
ANSWER: Charged in parallel and then discharged in series
24) For producing large values of impulse currents, a number of capacitors are charged in
a. Parallel and discharged in series
b. Parallel and discharged in parallel
c. Series and discharged in series
d. Series and discharged in parallel
ANSWER: Parallel and discharged in parallel
8. 25) In large impulse generators, the spark gaps are generally
a. Sphere gaps
b. Hemispherical gaps
c. Square gaps
d. Either (a) or (b)
ANSWER: Either (a) or (b)
26) A Capacitance Voltage Transformer can be connected to a
a. High impedance device
b. Low impedance device
c. Relay coil
d. Only (b) and (c)
ANSWER: Only (b) and (c)
27) The attractive force between the electrodes of a parallel plate capacitor is
a. Directly proportional to the square of the applied voltage between plates
b. Directly proportional to the capacitance between the plates
c. Inversely proportional to the square of the separation between the plates
d. All of these
ANSWER: All of these
28) The series capacitor peak voltmeter is suitable for
a. Positive half cycle
b. Negative half cycle
c. Sinusoidal waveform
d. All of these
ANSWER: All of these
9. 29) For voltage measurements, the gap which gives highest accuracy is
a. Sphere gaps
b. Field gaps
c. Rod gaps
d. None of these
ANSWER: Sphere gaps
30) The sparkover voltage
a. Increases with humidity
b. decreases with the partial pressure of water vapour in air
c. Humidity effect decreases with the size of spheres
d. Humidity is minimum for uniform field gaps
ANSWER: Increases with humidity
31) The expected life at the rated stress can be determined by conducting long duration life tests at increased
stress for
a. Less than 1 hr
b. 1 hr to about 1000 hr
c. More than 1000 hr
d. None of these
ANSWER: 1 hr to about 1000 hr
32) Impulse testing of transformers is done using
a. Full wave standard impulse
b. Chopped wave standard impulse
c. Half wave standard impulse
d. Only (a) and (b)
e. None of these
10. ANSWER: Only (a) and (b)
33) Failure during switching impulse tests are can be determined by
a. Visible in oscillograms
b. Loud noise produced
c. External flashovers
d. All of these
ANSWER: All of these
34) For operating power frequency voltages, a surge arrester has to be a
a. Conductor
b. Non-conductor
c. Semiconductor
d. None of these
ANSWER: Non-conductor
35) For the measurement of radio interference voltages, the detector circuit is provided with a measuring device
to measure
a. Average value
b. Peak value
c. Quasi-peak value
d. All of these.
ANSWER: All of these.
36) Which tariff is most ideal tariff for the consumer?
a. Two part tariff
b. Three part tariff
c. Both (a) and (b)
d. None of the above
11. ANSWER: Three part tariff
37) Which among the following are included in the three part tariff?
i. Fixed charges
ii. Running charges
iii. Semi fixed charges.
a. i, ii and iii
b. i and ii
c. i and iii
d. ii and iii
ANSWER: i, ii and iii
38) What is the main disadvantage of two port tariff?
a. He has to pay semi fixed charges.
b. He has to pay fixed charges.
c. He has to pay running charges.
d. None of the above.
ANSWER: He has to pay fixed charges.
39) A variable charge is based on what?
a. Energy consumption
b. Maximum demand
c. Peak load demand
d. All of the above
ANSWER: Energy consumption
12. 40) Fixed charge is dependent on what factor?
a. Energy consumption
b. Maximum demand
c. Peak load demand
d. All of the above
ANSWER: Maximum demand
41) Two part tariff is charged on what basis?
a. Connected load
b. Units consumed
c. Maximum demand
d. Both (b) and (c)
ANSWER: Both (b) and (c)
42) Block rate tariff, where energy charge decreases with the increase in energy consumption,
a. Encourages the consumers for more consumption.
b. Discourages the consumers for more consumption.
c. Encourages the consumers to restrict their demand.
d. Encourages the consumers to improve the power factor.
ANSWER: Encourages the consumers for more consumption.
43) Which tariff is used by the small commercial consumers?
a. Maximum demand tariff
b. Block rate tariff
c. Three part tariff
d. Two part tariff
ANSWER: Block rate tariff
13. 44) Domestic consumers are charged _____________.
a. Flat demand tariff
b. Block rate tariff
c. Flat rate tariff
d. Off peak tariff
ANSWER: Block rate tariff
45) Flat rate tariff is charged on what basis?
a. Connected load.
b. Units consumed.
c. Maximum demand.
d. All of these
e. None of these
ANSWER: Units consumed.
46. A transformer costing Rs 90,000 haws a useful life of 20 years. Determine the annual
depreciation charge using straight line method. Assume salvage to be 15,000.
a. 4000
b. 3750
c. 4350
d. 3500
ANSWER: b. 3750
47. The amendment in created programmes/vendor-created is called
A) patches B) antiviruses
C) holes D) fixes
Answer: A) patches
14. 48. The example of artificial fibre is
a. Rayon
b. Cotton
c. Flax
d. Silk
ANSWER: Rayon
