Wireman – Semester 1 Module 8: AC Circuits
191 : What is the value of form factor?
A : 1.23
B : 1.11
C : 0.81
D : 0.707
192 : What is the RMS value of alternating voltage?
193 : What is the name of AC value is illustrated in dotted lines?
A : Effective value
B : Peak value
C : Average value
D : Instantaneous value
194 : Which quantity is rotating at a constant angular velocity?
A : Scalar quantity
B : Vector quantity
C : Phasor quantity
D : Algebraic quantity
195 : What is the shape of the waveform of A/C?
A : Sine wave
B : Square wave
C : Sawtooh wave
D : Pulsating wave
196 : Which AC circuit wave form is illustrated?
A : Pure resistive circuit
B : Pure inductive circuit
C : Resistive and inductive circuit
D : Inductance and capacitance circuit
197 : What is the inductive reactance of a coil having 20H inductance operating at 50 Hz supply frequency?
A : 6252Ω
B : 6273Ω
C : 6284Ω
D : 6382Ω
198 : Which formula is used to find impedance of a RLC series circuit?
199 : Which formula is used to calculate power factor (Cosθ) of an AC circuit?
200 : Which formula is used to calculate reactive power (Pr)?
A : Pᵣ = VI cosθ
B : Pᵣ = VI sinθ
C : Pᵣ = Wθ
D : Pᵣ = VI tanθ
201 : What is the formula for calculating admittances (Y) of a AC parallel circuit?
202 : What is the reciprocal of resistance in AC parallel circuit?
A : Reactance
B : Admittance
C : Conductance
D : Susceptance
203 : What is the S.I unit of frequency?
A : Kilo Hertz
B : Hertz
C : Mega Hertz
D : Giga Hertz
204 : What is power in pure inductive AC circuit?
A : 0 KW
B : 1 KW
C : 2 KW
D : 5 KW
205 : What is inductive reactance of AC inductive circuit if the inductance value is 4H?
A : 1256 ohms
B : 1258 ohms
C : 1260 ohms
D : 1262 ohms
206 : What is the name of total opposition offered by RLC series circuit?
A : Inductive reactance
B : Capacitive reactance
C : Impedance
D : Admittance
207 : Which formula is used to calculate the impedance (Z) of R.L.Series circuit?
208 : What is the formula for power in AC RC series circuit?
A : VI
B : VI cos
C : VI sin
D : VI
209 : What is effect of current in a RC parallel circuit?
A : IC Leads IR by 90°
B : IC Lags IR by 90°
C : IR Leads IC 90°
D : IR & IC are in phase
210 : What is impedance in AC, RL series circuit if resistance is 3 ohm and inductive reactance 4 ohm?
A : 3 ohm
B : 5 ohm
C : 7 ohm
D : 12 ohm
211 : What is the relationship between line and phase current in delta connection?
212 : Which formula to find phase voltage in 3 phase star connection?
213 : What is the reactive power, if the active power is 4 Kw, and the apparent power is 5 Kw in a 3 phase circuit?
A : 1 Kw
B : 2 Kw
C : 3 Kw
D : 4 Kw
214 : Where the artificial neutral is required for measuring phase voltage in 3 phase circuit?
A : 3 wire star connected system
B : 4 wire star connected system
C : 3 wire delta connected system
D : 4 wire delta connected system
215 : What is the power factor, if one wattmeter reads zero and other reads some positive reading in two wattmeter method of 3 phase power measurement?
A : Unity
B : Above 0.5
C : 0.5
D : Below 0.5
216 : Which is the formula to calculate the power consumed in a balanced load in star or delta connected system?
217 : What is the name of star point in star connection system?
A : Neutral point
B : Cross point
C : Tapping point
D : Phase tapping wire
218 : What will be the neutral current in 3 phase-unbalanced circuits?
A : One
B : More than one
C : Zero
D : Not zero
219 : In a 3 balanced star connected system having a phase voltage of 240V calculate the line voltage in the circuit?
A : 400 V
B : 415 V
C : 430 V
D : 450 V
220 : Which type of the power measurement is used for balanced and unbalanced louds in 3 phase system?
A : Single wattmeter method
B : Two wattmeter method
C : Three wattmeter method
D : Voltmeter and ammeter method
221 : What is the purpose of system earthing?
A : To maintain ground at zero potential
B : To reduce the load current
C : To protect the equipment from over load
D : To reduce the losses
222 : Why earth resistance value required to keep very low?
A : For quick current flow
B : For easy measurement
C : For low power consumption
D : For low voltage drop
223 : What is the minimum length of the earth electrode pipe?
A : 1.5 metre
B : 2 metre
C : 2.25 metre
D : 2.5 metre
224 : What is the minimum size of the copper plate electrode?
A : 30cm to 30cm
B : 60cm X 40cm
C : 60cm X 50cm
D : 60cm X 60cm
225 : What will happen to the value of earth resistance, if length of the earth pipe is increased?
A : Remain same
B : Increases
C : Decreases
D : Infinity
226 : Which type of holder is to be earthed as per BIS?
A : Angle holder
B : Bracket holder
C : Battern lamp holder
D : Pendant lamp holder
227 : What is size of earth conductor used in power load?
A : 8 SWG
B : 10 SWG
C : 14 SWG
D : 20 SWG
228 : What is the range of good earth resistance?
A : High resistance
B : Very low resistance
C : Medium resistance
D : Very high resistance
229 : How earth resistance value mainted in summer?
A : Use new electrode
B : Use new coal and salt layer
C : Use new earth wire
D : Use water and maintain wet condition
230 : Which method is used to reduce earth resistance?
A : Reducing the pit depth for earthing
B : Increasing the depth of earth pit
C : Decreasing the length of the electrode
D : Connecting number of earth electrode in parallel
231 : Which instrument is used to measure earth resistance?
A : Megger
B : Ohm meter
C : Wheatstone bridge
D : Earth tester
232 : What principle earth tester works?
A : Potential dividing method
B : Fall of potential method
C : Fall of resistance method
D : Current dividing method
233 : What is the reason for supplying AC to the electrodes for measuring earth resistance?
A : AC is easily available
B : Protect the coils in the meter
C : Reduce the value of current in the meter
D : Avoid the effect of electrolytic Emf interference
234 : How many primary winding required in ELCB?
A : One primary winding
B : Two primary windings
C : Three primary windings
D : Four primary windings
235 : What is the purpose of the ELCB?
A : Control the fault circuit current
B : Protect the residual current
C : Protect the equipment from over load
D : Protect the circuit from short circuit