If the fault current is 2000 A, the relay plug setting is 50% and the CT ratio is 400/5, the plug setting multiple will be

A fixed step by step procedure for finding the solution of a problem on computer is called

Bulk power transmission over long HVDC lines are preferred on account of

A 3 phase, 6 pole induction motor operates on 440 V, 50 Hz, supply. If the actual speed of the motor is 960 rpm the slip will be

Ns = 120f/P
Slip=(Ns-Nr)/Ns
Ns = 1000 and Nr = 960
from equation of slip, S = (1000-960)/1000
S = 0.04 or 4%

The efficiency of a transformer at full load, 0.8 p.f. lag is 90%. Its efficiency at full load, 0.8 p.f. lead will be

Efficiency= output power/input power
efficiency = (v*i*cosφ)/((v*i*cosφ)+(x² Pc)+(Pi)) x=fractional part of full load

Due to skin effect

Skin Effect:
tendency of the current to crowd near the conductor surface.

Skin effect is proportional to frequency, conductor diameter and permiability.
Skin effect increases effective resistance of conductor.
In DC, no skin effect.