Quiz: Electrical Engineering 23 Dec 2020

Quiz: Electrical Engineering
Exam: SSC JE
Topic: Miscellaneous

Each question carries 1 mark.
Negative marking: 1/3 mark
Time: 10 Minute

Q1. A 4 A source has a shunt internal resistance of 45 Ω. The maximum power that can be delivered to a load is
(a) 560 W
(b) 380 W
(c) 180 W
(d) None of above

Q2. What is the maximum safe current flow in a 9 Ω, 36 W resistor?
(a) 2 A
(b) 4 A
(c) 7 A
(d) None of the above

Q3. Synchronous condensers when operated at power factor ranging from lagging through unity to leading for voltage control, are called the
(a) Voltage Booster
(b) Synchronous Reactors
(c) Mechanical synchronizers
(d) None of the above

Q4. A pony motor is basically a
(a) small induction motor
(b) dc series motor
(c) dc shunt motor
(d) None of the above

Q5. The purpose of feed back transformer and diode in complimentary commutated inverter is to
(a) improve the power factor of the load
(b) return the trapped energy to the source
(c) improve the input power factor
(d) all of the above

Q6. A motor armature supplied through phase-controlled SCRs receives a smoother voltage shape at
(a) High motor speed
(b) Low motor speed
(c) Rated motor speed
(d) None of the above

Q7. SF6 is transported in
(a) Solid form
(b) Gas cylinder
(c) Liquid form in cylinder
(d) Air cylinder

Q8. Which of the following parameter will remain constant during charging and discharging of a capacitor?
a) Power
b) Current
c) Time constant
d) Voltage

Q9. What is the value of initial current while charging a capacitor?
a) High
b) Low
c) 0
d) Cannot be determined

Q10. The actuating quantity for the relays may be
a) Magnitude
b) frequency
c) phase angle
d) Any of the above

Solution

S1. Ans.(c)
Sol. Source is connected across shunt resistance i.e., Norton’s equivalent circuit so
Here, I_N = 4 A and R_N = 45 Ω. For maximum power in the load, R_L=R_N = 45 Ω.
Therefore, current through load = I_N/2 = 4/2 = 2 A
∴ P_max = (2) ² × R_L = (2) ² × 45 = 180 W

S2. Ans.(a)
P = I²R or I = √(P/R)=√(36/9) = 2A

S3. Ans.(b)
Sol. Synchronous Reactors

S4. Ans.(a)
Sol. small induction motor

S5. Ans.(b)
Sol return the trapped energy to the source

S6. Ans.(a)
Sol. High motor speed

S7. Ans.(c)
Sol. Liquid form in cylinder

S8. Ans(c)
Sol. The time constant in a circuit consisting of a capacitor is the product of the resistance and the capacitance (which are fixed for a particular capacitor). Smaller the time constant, faster is the charging and discharging rate and vice versa.

S9. Ans(a)
Sol. The initial current of a capacitor is very high because the voltage source will transport charges from one plate of the capacitor to the other plate.

S10. Ans(d)
Sol. Any of the above

Leave a comment

Your email address will not be published. Required fields are marked *