Quiz: Electrical Engineering
Exam: UPSSSC JE
Topic: Power generation, transmission and distribution
Each question carries 1 mark.
Negative marking: 1/4 mark
Time: 10 Minute
Q1. Skin effect exists in
(a)cable carrying dc current
(b)dc transmission line only
(c)ac transmission line only
(d)dc as well as ac transmission line
Q2. Bundled conductors reduce
(a)surface electric stress of conductor
(b)increase the line reactance
(c)decrease the line capacitance
(d)None of the above
Q3. In interconnected grid system, more efficient plants are used as
(a) peak load stations
(b) base load stations
(c) both (i) and (ii)
(d) none of the above
Q4. The main advantage(s) of hydro-plants is/are
(a) low operating cost
(b) can be started and loaded quickly
(c) can be used as base and peak loads
(d) all of the above
Q5. Which type of insulators are used on 132 kV transmission line?
(a)Pin type
(b)Disc type
(c)Shackle type
(d)Pin and shackle type
Q6. A load draws active power (P), apparent power (S) and reactive power (Q) from the line. The power factor of the load is
(a) S/P
(b) P/Q
(c) P/S
(d) Q/P
Q7. Ferranti effect happens in transmission line when the line is
(a)short and loaded
(b) long and loaded
(c)Long and unloaded
(d)None of these
Q8. In a transmission line having negligible resistance the surge impedance is
(a)√(L+C)
(b)√(C/L)
(C)√(1/LC)
(d)√(L/C)
Q9. Grading of cables
(a)reduce insulation cost and increase current rating.
(b)reduce insulation cost but decrease current rating.
(c)Increases both
(d)None of above
Q10. The annual working cost of a power plant is represented by the formula Rs. (a + b kW + c kWh) where the various terms have their usual meaning. The value of a is maximum for
(a) Hydro power plant
(b) Steam power plant
(c) Diesel power plant
(d) Nuclear power plant
Solution
S1. Ans. (c)
Skin effect exists in ac transmission line only.
S2. Ans. (a)
Bundled conductors reduce surface electric stress of conductor.
S3. Ans.(b)
Sol. A base load station supplies almost a constant load throughout the day i.e. for 24 hours.
Therefore, more efficient plants are used as base load stations.
S4. Ans.(d)
Sol. all of the above
S5. Ans.(b)
Sol. Disc type
S6. Ans.(c)
Sol. Power factor = (Active power)/(Apparent power)=(VI cosϕ)/VI=cosϕ=P/S
S7. Ans.(c)
Sol. Ferranti effect happens in transmission line when the line is long and unloaded.
S8. Ans.(d)
Sol. In a transmission line having negligible resistance the surge impedance is √(L/C)
S9. Ans.(a)
Sol. Grading of cables reduce insulation cost and increase current rating.
S10. Ans.(d)
Sol. The annual fixed cost (a) of nuclear power plant is very high because sophisticate technology is required for the manufacture of nuclear power plant.
