A single-phase, 230V/110V, 50 Hz transformer takes an input of 350 VA at no load while working at rated voltage. The core loss is 110W. The no-load power factor is_________. 

A 100kVA, 230/115 V, 50Hz, single phase transformer is designed for a maximum efficiency to occur at 75 percent of the full loading condition. Its iron and full load copper losses are referred as P1 and P2, respectively. Then the ratio of P1 to P2 at Maximum efficiency is given as: 

A single-phase transformer with a ratio of 440/110-V takes a no-load current of 5A at 0.2 p.f lagging. If the secondary supplies a current of 120 A at a p.f. of 0.8 lagging, the approximate current taken by primary is_____A

The iron loss of a transformer at 400 Hz is 10 W. Assuming that eddy current and hysteresis losses vary as the square of flux density, the iron loss of the transformer at rated voltage but at 50 Hz would be _____watt.

As compared to ∆ − ∆ bank, the capacity of the V − V bank of transformers is ......... %. 

A 500 turns coil has an inductance of 3.5 mH. If the number of turns are increased to 1000, all other parameters remain the same, the inductance will be

A certain coil has a resistance of 20 Ω and an inductance of 0.04 H. If the instantaneous current flowing in it is represented by i = 5 sin 300 t + 0.8 sin 900 t amperes. The power delivered to load is

Two circuits, the impedances of which are given by Z1=15 + j12 ohms and Z2=8 − j5 ohms are connected in parallel. If the potential difference across one of the impedance is 250 + j0 V, the total current is_______A

Power consumed by a balanced 3-phase, 3-wire load is measured by the two- wattmeter method. The first wattmeter reads twice that of the second. Then the load impedance angle in radians is

A pure resistance of 50 ohms is in series with a pure capacitance of 100 microfarads. The series combination is connected across 100V, 50 Hz supply. The impedance of the circuit is_________ Ω.