C.13 Indicate whether the following statements are correct or not then correct the incorrect statements 1) the multi pulse selected notching technique used in inverter is used to eliminate the low order harmonics and to reduce switching frequency, 2) In 3-phase half-controlled half-wave rectifier, the firing angle can be varied from 0 to 180 degrees while in 6-phase half-controlled half-wave rectifier can be varied from 0 to 150 degrees Q.14 Indicate whether the following statements are correct or not then correct the incorrect statements 1) In rectifier circuits, lower pulse number and connecting either primary or secondary of 3- phase winding in delta will reduce the harmonics content of the drawr. current 2) In thyristor triggering, the pulse width should be long enough to permit holding current to be established