Quiz: Electrical Engineering 18 May 2020

Quiz: Electrical Engineering

Exam: UPSSSC JE

Topic: Miscellaneous

 

Each question carries 1 mark.

Negative marking: 1/4 mark

Time: 10 Minute

 

 

Q1. The potential difference of an energy source that provides 100 mJ of energy for every microcoulomb of charge that flows is

(a) 5 V

(b) 10 V

(c) 100 V

(d) 50 kV

 

 

Q2. A d.c. shunt motor takes 5A at 100 V when running light. Shunt field resistance is 50Ω and armature resistance is 0.2Ω. What is the driving power?

(a) 412 W

(b) 298 W

(c) 305 W

(d) 204 W

 

 

Q3. The current in a circuit having constant resistance is doubled. The power increases

(a)  times

(b) 3 times

(c) 4 times

(d)  times

 

 

Q4. In case of liquids, Ohm’s law is

(a) fully obeyed

(b) partially obeyed

(c) Both

(d) none of the above

 

 

Q5. A d.c. circuit usually has ………. As the load.

(a) resistance

(b) inductance

(c) capacitance

(d) both inductance and capacitance

 

 

Q6. The purpose of load in an electric circuit is to

(a) increases the circuit current

(b) utilize electrical energy

(c) decrease the circuit current

(d) none of the above

 

 

Q7. When cells are arranged in parallel

(a) the current capacity increases

(b) the current capacity decreases

(c) the e.m.f. increases

(d) the e.m.f. decreases

 

 

 

Q8. Fringing effect is ignored in a magnetic circuit if air-gap is

(a) large

(b) small

(c) very large

(d) none of the above

 

 

 

Q9. The nature of armature winding of a d.c. machine is decided by ………

(a) front pitch

(b) commutator pitch

(c) back pitch

(d) none of the above

 

 

 

Q10. A triplex wave winding will have …….. parallel paths.

(a) 6

(b) 2

(c) 4

(d) none of the above

 

 

 

 

Solution

S1. Ans.(c)

Sol.  100 kV

 

S2. Ans.(b)

Sol.  A; 3 A;  = 100 – 3 × 0.2 = 99.4 V

Driving power =  = 99.4 × 3 = 298 W

 

 

S3. Ans.(c)

 

Sol.  P ⍺ I2

 

 

S4. Ans.(a)

 

Sol. Fully obeyed.

 

 

S5. Ans.(a)

 

Sol. As there is frequency component missing with dc current required in the other loads.

 

 

 

S6. Ans.(b)

 

Sol. The main purpose is to utilize electrical energy for comfort of mankind.

 

 

S7. Ans.(a)

 

Sol. When cells are arranged in parallel the current capacity increases

 

 

S8. Ans.(b)

 

Sol. The fringing effect results from the presence of the air gap in the magnetic circuit. The main consequence of the fringing effect is to make the magnetic flux density of the air gap different from the flux density of the core due to the path of the flux.

 

S9. Ans.(b)

 

Sol. It is the commutator pitch the determines the grouping to coils in series and parallel. In other works, it is the commutator pitch that determines as to how many parallel paths, each consisting of equal number of coils in series, will be formed. Hence, the nature of winding is determined by the Commutator pitch

 

 

S10. Ans.(a)

 

Sol. With an n-plex wave winding, the number of parallel paths is 2nwhere n = 2, 3 etc. and stands for duplex, triplex etc.

Hence, a triplex wave winding will have 2 × 3 = 6 parallel paths

 

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