TS ECET EEE 2016-10

1.In a series RLC circuit R = 3 ohm, X =j 6 ohm,X =-j2ohm. What is the voltage applied across the combination if the series current is 10 L-143° A

A. 50 L-30° V
B. 50 L-90° V
C. 50 L-60° V
D. 30 L-90° V

Answer : 50 L-90° V
Explain:-

2. Three circuit elements, R=2 ohm,Xl=j5 ohm, Xc=-j10 ohm are connected in parallel. If the supply frequency is 50 Hz, find the input admittance

A. (0.5-j 0.1) mho
B. (2-j 5) mho
C. (2+j 5) mho
D. (5-j1) mho

Answer : (0.5-j 0.1) mho
Explain:-

3. Selectivity of a resonating circuit is defined as

A. (Band Width) (Resonance Frequency)
B. (Resonance Frequency)/ (Band Width)
C. (Resonance Frequency)² x (Band Width)
D. (Resonance Frequency) x (Band Width)²

Answer : (Resonance Frequency)/ (Band Width)
Explain:-

4. The property of resonance of parallel RLC circuit is

A. Power factor is zero
B. Current is maximum
C. Net impedance circuit is minimum
D. Current is minimum

Answer : Current is minimum
Explain:-

5. In a balanced delta connection of a three phase system, the line currents are behind the respective phase currents

A. 60°
B. 30°
C. 120°
D. 90°

Answer : 30°
Explain:-

6. A three phase, 400 V, 50 Hz source supplied power to a 3 phase balanced motor load. If the line current is 25 A, power factor being 0.8, obtain the real power consumed

A. 13.856 kW
B. 1.3856 kW
C. 138.56 kW
D. 100 kW

Answer : 13.856 kW
Explain:-

7. An induction motor draws a three phase power and two wattmeter measurement is applied to find the total power. If W, and W, are the watt meter readings, find the total three phase real power (P) and reactive power (Q)

A. P = (W1 + W2), Q = 1.732 x (W1 + w2)
B. P = (W1 - W2), Q = 1.732 x (W1 - w2)
C. P = (W1 + W2), Q = 1.732 x (W1 - w2)
D. P = 1.732 x (W1 + w2), Q = (W1 + W2)

Answer : P = (W1 + W2), Q = 1.732 x (W1 - w2)
Explain:-

8. If a transformer core has air gaps, then

A. Reluctance of magnetic path is decreased
B. Hysteresis loss is decreased
C. Magnetizing current is greatly increased
D. Eddy current is increased

Answer : Magnetizing current is greatly increased
Explain:-

9. A 230 V / 2300 V single phase transformer takes no load current o 5 A at 0.25 power factor lagging. The core loss is

A. 300.2 W
B. 192.5 W
C. 287.5 W
D. 212.6 W

Answer : 287.5 W
Explain:-

10. A transformer has 200 W as iron loss at full load. The iron loss at half load will be

A. 50 W
B. 100 W
C. 400 W
D. 200 W

Answer : 200 W
Explain:-