1. A 6-pole, 50 Hz, 3 phase induction motor is running at 950 rpm and has rotor Cu loss of 5 kW. Its rotor input is (a) 100 kW (b) 10 kW (c) 95 kW (d) 5.3 kW 2. Distribution transformer have core losses (a) More than full load copper loss (b) Equal to full
1. A transmission line of 50 W characteristic impedance is terminated with a 100 W resistance. The minimum impedance measured on the line is equal to (a) 0 (b) 25 W (c) 50 W (d) 100 W 2. A cavity resonator can be represented by (a) An LC circuit (b) An LCR circuit (c) A
1. The reason of preferring FETs to bipolar transistors in integrated circuits is that (a) they occupy very small space (b) it has become a tradition (c) fabrication of circuit is easy (d) it is cheaper 2. Out of the following devices, the fastest switching device is (a) JFET (b) BJT (c) MOSFET (d) Triode
1. Transformer cores are laminated to reduce (a) eddy current loss (b) hysteresis loss (c) both hysteresis and eddy current loss (d) copper loss 2. The regulation of a transformer is negative when the load is (a) purely resistive (b) purely inductive (c) capacitive (d) regulation can never be negative 3. Distribution transformers preferably should
1. The charge on an isolated conductor resides (a) At the conductor surface (b) Inside the conductor (c) Partly at the surface and partly inside the conductor (d) None of these 2. Dielectric strength of a material depends on (a) Temperature (b) Thickness (c) Moisture content (d) All of these 3. Electromagnetic waves may be
1. The effect of increasing the length of air-gap in the induction motor will be increase the (a) Power factor (b) Speed (c) Magnetising current (d) Air gap flux 2. In 3ph induction motor, the rotor field rotates at synchronous speed with respect to (a) Stator (b) Rotor (c) Stator flux (d) None of these.
1. Which of the following has the longest wavelength? (a) HF (b) VHF (c) UHF (d) SHF 2. A power chopper converts (a) a.c. to .d.c (b) d.c. to d.c. (c) d.c. to a.c. (d) a.c. to a.c. 3. A thyristor controlled reactor is used to get (a) variable resistance (b) variable capacitance (c) variable
1. The advantage of transmitting power at high voltage is (a) magnitude of current will be small (b) it will reduce the voltage drop in the line (c) power loss will be less (d) all of these 2. In the protection scheme, relay functions as a (a) switching device (b) sensing device (c) breaking device
1. Minimum number of J-K flip-flops needed to construct a BCD counter is (a) 2 (b) 3 (c) 4 (d) 5 2. Consider the following Any combination circuit can be built using (1) NAND gates (2) NOR gates (3) EX-OR gates (4) Multiplexers Which of these are correct? (a) 1, 2 and 3 (b) 1,
1. In a dc machine, for the same value of f, Z and N, which one of the following statements is correct? (a) Armature emf is more with wave winding than with lap winding. (b) Armature emf is less with wave winding than with lap winding. (c) Armature emf depends on whether the machine is
