a) Is stronger where the lines of force are in the same direction b) Is stronger where the lines are in opposite direction c) Has the same strength as for one magnet d) Is weakest where the lines are in the same direction Ans: (a)
a) Acts as bar magnet only when there is no current in the conductor b) Acts as bar magnet only when the current flows in the coil c) Is similar to ring magnet because there is no air gap d) Acts as bar magnet only when it has iron core Ans: (b)
a) Energy b) Power c) Voltage d) Torque Ans: (d)
a) Without any additional magnetic field b) Move the conductor from weaker field toward stronger field c) Move the conductor from stronger field toward a weaker field d) Produce the motion of the conductor but not rotation Ans: (c)
a) 6.37 volts b) 10 volts c) 14 volts d) 28 volts Ans: (c)
a) Each has its peak value at the same time b) Each has its minimum value at the same time c) One has its peak value when the other has zero value d) One has its positive peak when the other has its negative peak Ans: (c)
a) 1-amp. D.c. current b) 50-amp. D.c. current c) 1-amp. 60 cycles a.c. current d) 1-amp. 490 cycles a.c. current Ans: (d)
a) Reverses its direction b) Has the same direction c) Has phase angle of 180 degree d) Alternates at 1.4 time the frequency of the applied voltage Ans: (a)
a) High r.m.s. value b) Varying magnetic field c) Stronger field than direct current d) Constant magnetic field Ans: (b)
a) The same b) Double c) Quadrupled d) One-quarter Ans: (c)
a) Less than one ohm b) 10.5 ohms c) 104 ohms d) More than 1 M Ω Ans: (b)
a) Zero resistance and high inductance b) Infinite resistance and zero inductance c) Infinity resistance and normal inductance d) Zero resistance and inductance Ans: (b)
a) Reduces the amplitude of alternating current b) Increases the amplitude of alternating current c) Increases the amplitude of direct current d) Has a back e.m.f. opposing the voltage output of a battery Ans: (a)
a) Increases with lower frequency b) Increases with lower inductance c) Depends on the factor 2π d) Decreases with the higher frequencies Ans: (c)
a) 0° b) 60° c) 45° d) 90° Ans: (c)