a) Long time constant b) Large self-induced voltage across the inductance c) Source of the voltage caused by IR drop across the resistance d) Low resistance of the open switch Ans: (b)
a) Voltage across the inductor leads the voltage across the reactance by 90° b) Resistance branch current is 90° out of phase with the inductive branch current c) Resistive and inductive branch current are 180° out of phase d) Inductive and resistive branch currents are in phase Ans: (b)
a) Can produce the induced voltage as the current decreases when the switch is opened b) Cannot produce the induced voltage as the voltage applied has the one polarity c) Produces more induced voltage when the switch is closed than the switch is opened d) None of the above Ans: (a)
a) Maximum value b) Maximum change in magnetic field c) Minimum change in magnetic field d) 0.707 × Peak Ans: (b)
a) 60 mh b) 300 mh c) 150 mh d) 600 mh Ans: (d)
a) Iron core has maximum eddy-current losses b) Laminated iron core has minimum eddy-current losses c) Power-iron core has the maximum eddy-current losses d) Air core has the minimum eddy-current Ans: (d)
a) 0° b) 180° c) 360° d) 90° Ans: (d)
a) Ceramic capacitors must be connected in the correct polarity b) Electrolytic capacitor must be connected in the correct polarity c) Mica capacitors are available in capacitance value of 1 to 10 micro-farad d) Air capacitors have a blackband to indicate the outside foil Ans: (b)
a) 33.333 b) 50 c) 1000 d) 100 Ans: (d)
a) Of high peak value b) Charging current can flow c) Discharge current can flow d) Varying voltage produces the charging and discharging currents Ans: (d)
a) Decreases b) Increases c) Remains same for frequencies d) Decreases as the voltage increases Ans: (a)
a) Depends on the current rating of the battery b) Is greater for larger values of capacitances c) Is smaller for larger values of capacitances d) Is zero for any value of capacitance Ans: (d)
a) Voltages across R and Xc are in phase b) Voltages across R and Xc are 180° out of phase c) Voltages across R leads the voltages across Xc by 90° d) Voltage across R lags the voltage across Xc by 90° Ans: (c)
a) True b) False Ans: (a)
a) True b) False Ans: (a)