A dc voltage with ripple is given by $$v\left( t \right)\,\,\,\, = \,\,\,\,\left[ {100 + 10\sin \left( {\omega t} \right) - 5\sin \left( {3\omega t} \right)} \right]$$ volts. Measurements of this voltage $$v\left( t \right),$$ made by moving-coil and moving iron voltmeters, show readings of $${V_1}$$ and $${V_2}$$ respectively. The value of $${V_2} - {V_1},$$ in volts, is _______.

A 4-pole, lap-connected, separately excited dc motor is drawing a steady current of 40 A while running at 600 rpm. A good approximation for the waveshape of the current in armature conductor of the motor is given by

A DC shunt generator delivers 45 A at a terminal voltage of 220 V. The armature and the shunt field resistance are 0.01 Ω and 44 Ω respectively. The stray losses are 375 W. The percentage efficiency of the DC generator is ______.

If an ideal transformer has an inductive load element at port 2 as shown in the figure below, the equivalent inductance at port 1 is