Synopsis of Electrical Engineering

Important Multiple Choice questions on Power Systems 1.        For transmission line which one of the following relations is true? A)      AD-BC=1 B)       –AD-BC=1 C)       AD-BC=-1 D)      AD-BC=0 2.        For a given base voltage and base volt-amp, the per unit impedance value of an element is X. what will be the per-unit impedance value of this element when the voltage and volt-amp bases are both doubled? A)      4X B)       2X C)       X D)      0.5X 3.        A 3-phase transmission line has its conductors at the corners of an equilateral triangle with side 3m. the diameter of each conductor is 1.63 cm. the inductance of the line per phase per km is A)      1.232 mH B)       1.182 mH C)       1.093 mH D)      1.043 mH 4.        A cable has inductance of 0.22mH per km and capacitance of 0.202 micro farads per km. the surge impedance of the cable is A)      28 ohms B)       33 ohms C)       42 ohms D)      50 ohms 5.        The capacitanc

Important Multiple Choice Questions On Power Systems 1.        Plug-setting of a relay can be altered by varying A)      Number of ampere-turns B)       Air gap of magnetic path C)       Adjustable back up stop D)      None of these 2.        If the time of operation of a relay for unity TMS is 10 sec, the time of operation of 0.5 TMS will be A)      20 Sec B)       5 Sec C)       10 Sec D)      None of these 3.        Where the voltages are high and current to be interrupted is low, the breaker proffered is A)      Air blast CB B)       Oil CB C)       Vacuum CB D)      Any of these 4.        Resistance switching is normally employed in A)      All breakers B)       Bulk oil breakers C)       Minimum oil breakers D)      Air blast circuit breakers 5.        For protection of rotating machines against lightning surges a combination of A)      Lighting conductor and capacitors are used B)       Lighting conductor and lighting arrestors