Ques.91. The permissible variation of frequency in power system Ps is (SSC – 2009)
± 1%
± 3%
± 5%
± 10%
Answer.2. ± 3%
Explanation
According to CENTRAL ELECTRICITY REGULATORY COMMISSION OF INDIA
Ideal Range of frequency variation
f = 50 ± 1%
49.5 to 50.5 Hz
Practical permissible Range of frequency variation
f = 50 ± 3%
48.5 to 51.5 Hz
The grid frequency should be maintained at 48.6 Hz. and above at all times.
Ques.92. In a series R-L-C circuit, susceptance is equal to (SSC – 2009)
1/X
1/R
R/Z2
X/Z2
Answer.4. X/Z2
Explanation:-
In electrical engineering, susceptance (B) is the imaginary part of admittance, where the real part is conductance. The inverse of admittance is impedance, where the imaginary part is reactance and the real part is resistance.
The general equation defining admittance is given by
where
Y is the admittance, measured in Siemens.
G is the conductance, measured in Siemens.
j is the imaginary unit and
B is the susceptance, measured in Siemens.
The admittance (Y) is the inverse of the impedance (Z)
Ques.93. The current read by the ammeter A in the AC circuit shown in the following figure is (SSC – 2009)
9A
5 A
3 A
1 A
Answer.2. 5 A
Explanation:-
Current for a Parallel RLC Circuit
Is = 5A
Ques.94. The voltage across the various elements are marked, as shown in the figure given below. The maximum input voltage is (SSC – 2009)
27 V
24 V
10 V
5 V
Answer.4. 5 V
Explanation
Maximum Input voltage in series RLC circuit
Ques.95. The principle of dynamically induced emf is utilized in (SSC – 2009)
Choke
Transformer
Thermocouple
Generator
Answer.4. Generator
Explanation:-
In dynamically induced emf the magnetic field system is kept stationary, and the conductor is moving, or the magnetic field system is moving, and the conductor is stationary thus by following either of the two processes the conductor cuts across the magnetic field and the emf is induced in the coil. Hence the emf induced in a coil due to the relative motion of the conductor and the magnetic field is called dynamically induced emf.
Dc generator works on the principle of dynamically induced emf. Whenever a conductor cuts magnetic flux, dynamically induced e.m.f. is produced in it according to Faraday’s Laws of Electromagnetic Induction. This e.m.f. causes a current to flow if the conductor circuit is closed
Ques.96. The rating of fuse is expressed in terms of (SSC – 2009)
Amperes
Volts
VAR
KVA
Answer.1. Amperes
Explanation:-
Fuses are ‘overcurrent protection devices’ and therefore will be rated in current units, i.e. Amperes. A fuse opens or “blows” and opens the circuit when the current (amperes) exceeds a preset limit.
Ques.97. When the frequency of the source voltage decreases, the impedance of a parallel RC circuit (SSC – 2009)
Increase
Decrease
Remain Same
Decrease to zero
Answer.2. Decrease
Explanation
In parallel circuit 1/Z = 1/R + 1/Xc.
Since Xc = 1/(2πfc) which is Xc is inversely proportional f.
Thus in the parallel circuit the higher the resistance the lower the total resistance(impedance) therefore if the frequency decrease, the impedance will be decreased.
Ques.98. The reactance offered by a capacitor to alternating current of frequency 50 Hz is 20 Q. If frequency is increased to 100 Hz, reactance becomes_____ohms. (SSC – 2009)
5
5
10
15
Answer.3. 10
Explanation
Capacitive reactance
Xc = 1/2πf
Therefore XC1/XC2 = 2πf2/2πf1
= 20/XC2 =100/50
= XC2 = 10
For SSC JE SSC JE Basic Electrical Questions Solved (2009 – 2018) (Part-2) Click Here
For SSC JE SSC JE Basic Electrical Questions Solved (2009 – 2018) (Part-1) Click Here
For SSC JE SSC JE Electrical Transformer Questions Solved (2009 – 2018) Click Here
For SSC JE 2018 SET-1 Electrical paper with complete solutionClick Here
For SSC JE 2018 SET-2 Electrical paper with complete solutionClick Here
For SSC JE 2018 SET-3 Electrical paper with complete solutionClick Here
For SSC JE 2018 SET-4 Electrical paper with complete solutionClick Here
For SSC JE 2018 SET-5 Electrical paper with complete solutionClick Here