Q61. In an n-phase circuit, the phase angle between successive phase is given by

Q62. In a 3-phase, 4-wire, 400/230 V system, a lamp \(L_1\) of 100 W is connected to one phase and neutral and a lamp \(L_2\) of 150 W is connected to the second pahse and neutral. If the neutral wire is disconnected accidently, what will be the voltage across a 150 W lamp \(L_2\)?

Q63. A three-phase three-wire supply feeds a delta connected load consisting of three equal resistors. What will be the reduction in load if one of the resistor is removed?

Q64. Three capacitors of 100 \(\mu F\) each are connected in delta to a 400V, three-phase, 50 Hz supply. What will be the capacitance of each of the three capacitors if the same three capacitors are connected in star across the same supply to draw the same line current?

Q65. Three equal star-connected inductors take 8 kW at 0.8 power factor when connected to a 460 V three - phase 3-wire supply. If one of the inductor in phase – Y is short circuited, then the line current in phase-Y is ……………….. Assume RYB sequence.

Q66. Two wattmeters connected to measure power in a three-phase balanced load, if the reactive power input is 7.5 KVAR and power factor of the load is 0.8. Calculate the total power input.

Q67. Total instantaneous power supplied by a 3-phase ac supply to a balanced RL load is

Q68. Which of the following is not a source of reactive power?

Q69. Number of fundamental cut- sets of any graph will be

Q70. What are the properties of a tree in a network graph?
1. It consists of all the nodes of the graph.
2. If the graph has N number of nodes, the tree will have (N-1) branches.
3. There will be only one closed path in the tree.