Q.436 Two voltages e1 and e2 are given by 1 = 10sinɷt and e2 = 20 sin(ɷt+30) then
A. e1 leads by e2 by 30°
B. e2 leads e1 by 30°
C. e1 lags e2 by 30°
D. e lags e1 by 30°
Ans.: B
Q.437 The phase relationship between applied voltage and current in a phase capacitance is
A. in phase
B. current lags voltage by 90
C. current leads voltage by 90
D. out of phase
Ans.: C
Q.438 The resonance frequency of RLC circuit is
A. 1/ 2л√LC-R
B. 1/ 2л x√LC-RC
C. √LC/2л
D. 1/ 2л√LC
Ans.: D
Q.439 In a series RLC circuit the condition for resonance is
A. XL = Xc
B. Power factor becomes unity
C. Circuit becomes resistive
D. All of the above
Ans.: D
Q.440 In measurement of power by 2 wattmeter method one wattmeter shows zero and other wattmeter shows positive value. The power factor will be
A. unity
B. Zero
C. 0.5
D. less than 0.5
Ans.: C
Q. 441 In measurement system which of the following static characteristics
Are desirable?
A. Sensitivity
B. Accuracy
C. Reproducibility
D. all of the above
Ans.: D
Q.442 The smallest change in a measured variable in which an instrument will respond to
A. Resolution
B. Precision
C. Sensitivity
D. Accuracy
Ans.: A
Q.443 PMMC instrument can be used for measurement of quantity of
A. AC only
B. AC and DC both
C. DC only
D. None of above
Ans.: C
Q.444 In Analog instrument spring is used for generate
A. Deflection torque
B. Controlling torque
C. Damping torque
D. Eddy current generation
Ans.: B
Q.445 Open circuiting the secondary winding CT with primary still energized will result in
A. Unrestricted primary flux to generate high voltage in secondary
B. Possible insulation damage due to high voltage
C. Injury to careless operation
D. All of the above
Ans.: D
Q.446 Wheastone’s bridge is not preferred for precision measurement because of errors due to
A. Resistance of connecting leads
B. Resistance of contacts
C. Thermo-electric emf
D. All of the above
Ans.: D
Q.447 Maxwell’s bridge can be used for measurement of inductance with
A. Medium Q factor
B. High Q factor
C. Very low factor
D. Wide range of Q factor
Ans.: A
Q.448 Desauty’s bridge is used for measurement of
A. Medium Q inductance
B. Lossless capacitance
C. Low Q inductance
D. Capacitance with dielectric loss
Ans.: B
Q.449 Creeping in a single phase energy meter may be due to
A. Vibration
B. Overvoltages
C. Overcompensation of friction
D. All of the above
Ans.: C
Q.450 The purpose of the synchronizing control in a C.R.O is to
A. Adjust the amplitude of display
B. Control the intensity of the spot
C. Focus the spot on the screen
D. Lock the display of signal
Ans.: D