Quiz: Electrical Engineering

Date: 30/03/2020

Exam: UPSSSC- JE

Topic: Miscellaneous

Each question carries 1 mark.

Negative marking: 1/4 mark

Time: 10 Minute

Q1. The rms value of a sine wave is 100 A. Its peak value is

70.7 A

141 A

100 A

150 A

L1Difficulty 3

QTags Basic electrical engineering

QCreator Devbrat Kumar

Q2. Critical resistance in a DC generator increased by–

(a) increasing speed

(b) decreasing speed

(c) keeping field resistance constant

(d) continuously fluctuating field resistance

L1Difficulty 3

QTags DC Generator

QCreator Devbrat Kumar

Q3. Inter-poles are used in __________.

(a) lap wound machines

(b) wave wound machines

(c) both lap and wave wound machines

(d) None of these

L1Difficulty 3

QTags DC Generator

QCreator Devbrat Kumar

Q4. By increasing the transmission voltage to double of its original value, the same power

can be delivered keeping the line loss

(a) equal to original value

(b) half the original value

(c) double the original value

(d) one-fourth of original value

L1Difficulty 3

QTags Power generation, transmission and distribution

QCreator Devbrat Kumar

Q5. If the string efficiency is increased the voltage across the disc nearest to the conductor

(a) increases

(b) decreases

(c) remains the same

(d) none of the above

L1Difficulty 3

QTags Power generation, transmission and distribution

QCreator Devbrat Kumar

Q6. The sag of an overhead line is affected by

(a) conductor weight per unit length

(b) span and tension

(c) wind and temperature

(d) all of the above

L1Difficulty 3

QTags Power generation, transmission and distribution

QCreator Devbrat Kumar

Q7. In pure capacitive circuit angle the voltage with respect to current is

0⁰

90⁰ leading

90⁰ lagging

None of these

L1Difficulty 3

QTags Network & Circuit Theory

QCreator Devbrat Kumar

Q8. Which of the following is equivalent to 0.5 KWh?

1800000 W

1800000 J

3600000 J

36000000 J

L1Difficulty 3

QTags Electrical

QCreator Devbrat Kumar

Q9. Diversity factor is the ratio of ………………….

(a) Sum of maximum demands of consumers/system maximum demand

(b) Maximum demand of consumers/average demand.

(c) Demand of all consumers/average demand

(d) None of these

L1Difficulty 3

QTags Utilization of electrical energy

QCreator Devbrat Kumar

Q10. Plant capacity factor of a power plant may be calculated by the formula:

(a) (Average demand)/(Plant capacity)

(b) (Plant capacity)/(Average demand)

(c) (Sum of individual maxdemand)/(Max demand of plant)

(d) (Station output)/(Plant Hours of use)

L1Difficulty 3

QTags Utilization of electrical energy

QCreator Devbrat Kumar

SOLUTIONS

S1. Ans.(b)

Sol. Peak factor = (Max value)/(RMS value)

Peak factor = I_M/I_rms or V_m/V_rms

For pure sinusoidal wave, its value is 1.41.

S2. Ans.(a)

Sol. Critical resistance is maximum value of field resistance below which shunt generator will excite and voltage will be build up.

S3. Ans.(c)

Sol. Both lap and wave wound machines.

S4. Ans.(d)

Sol. Line loss ∝1/V^2

Line loss will be one fourth of the original value.

S5. Ans.(b)

Sol. String Efficiency = (Voltage across the string)/(n×Voltage across disc nearest to conductor)

S6. Ans.(d)

Sol. Sag,s=(wL^2)/8T

w = conductor weight per unit length

L = span

T = tension

Except these parameters sag also depends upon wind and temperature.

S7. Ans.(c)

Sol.

S8. Ans.(b)

Sol. 1 KWh= 3600000 J

S9. Ans.(a)

Sol. Diversity factor ((Sum of individual maximum demand))/((Coincident maximum demand of whole system) )

Diversity factor is always equals to or greater than 1 and used to determine the plant capacity.

S10. Ans.(a)

Sol. ▭(plant capacity factor=(peak load)/(plant capacity)×load factor)

=(Average demand)/(Plant capacity)

If peak load equals to plant capacity then load factor = capacity factor.