
UPSC_Exams > UPSC_Indian_Engineering_Services_Answer > UPSC_IES__EEE_QUESTION_PAPER_ANSWER_KEY 1) In a balanced 3phase 200 V circuit, the line current is 115.5 A. When the power is measured by two wattmeter method, one of the wattmeters reads 20 kW and the other one reads zero. What is the power factor of the load  A) 0.5  B) 0.6  C) 0.7  D) 0.8  View Answer   Answer : 0.5

2) A coil having an inductance of 0.5 H and a resistance of 60 ? is connected in series with a capacitance of 10 ?F. The coil is connected to 100 V ac supply. What is the source frequency and current flowing in the circuit under resonance condition  A) 7.121 Hz and 16.7 A  B) 7.121 Hz and 1.67 A  C) 71.121 Hz and 16.7 A  D) 71.21 Hz and 1.67 A  View Answer   Answer : 71.21 Hz and 1.67 A

3) Three equal impedances are first connected in delta across a 3phase balanced supply. If the same impedances are connected in star across the same supply then  A) Phase current will be onethird  B) Line current will be onethird  C) Power consumed will be onethird  D) Phase current will remain the same  View Answer   Answer : Phase current will be onethird

4) A Hurwitz polynomial D(s) must satisfy two conditions. One is the polynomial is real when s is real. What is the other condition  A) Roots of D(s) have real parts which are positive and nonzero  B) Roots of D(s) have imaginary parts which are negative  C) Roots of D(s) have real parts which are either zero or negative  D) Roots of D(s) have real parts which are positive or zero  View Answer   Answer : Roots of D(s) have real parts which are positive and nonzero

5) The unit impulse response of a system is given as c(t) = 4e^{t} + 6e^{2t}. The step response of the same system for t > 0 is equal to  A) 3e^{2t} + 4e^{t} + 1  B) 3e^{2t} + 4e^{t} + 1  C) 3e^{2t} + 4e^{t}  1  D) 3e^{2t}  4e^{t} + 1  View Answer   Answer : 3e^{2t} + 4e^{t}  1

6) Four ammeters Mx, M2, M3 and M4 with the ' following specifications are available. (Full scale, accuracy value as percentage of FS) M_{1} = 20 ± 0.10; M_{2} = 10 ± 0.20; M_{3} = 5 ± 0.50; and M_{4} = 1 ± 1.00 A current of 1 A is to be measured. To obtain minimum error in the reading one should select meter  A) M_{1}  B) M_{2}  C) M_{3}  D) M_{4}  View Answer   Answer : M_{4}

7) In an induction type energy meter, the steady speed attained by the rotating disc is Which of the above are correct ?  1) Proportional to the deflecting torque  2) Proportional to the resistance of the path of eddy currents  3) Inversely proportional to the effective readings of disc from its axis  4) Inversely proportional to the square of brake magnet flux  A) 1, 2 and 3 only  B) 1, 2 and 4 only  C) 2, 3 and 4 only  D) 1, 2, 3 and 4  View Answer   Answer : 2, 3 and 4 only

8) Consider the following functions :Which of the below functions are LC driving point impedance  1) (s^{2} + 1) (s^{2} + 3)/s(s^{2}+2)  2) s(s^{2} + 1) (s^{2}+3)/(s^{2}+0.5)(s^{2} + 2)  3) (s^{4} + 4s^{2} + 3)/s^{2 + 2S}  4) s^{4} + 2.5s + 1  A) 1, 2, 3 and 4  B) 2 and 3 only  C) 1 and 2 only  D) 3 and 4 only  View Answer   Answer : 1 and 2 only

9) A dc voltmeter has a sensitivity of 1000 Q/V. When it measures half full scale in 100 V range, the current through the voltmeter is  A) 100 mA  B) 50 mA  C) 1 mA  D) 0.5 mA  View Answer   Answer : 0.5 mA

10) Two wattmeter method is employed to measure power in a 3phase balanced system with the current coil connected in the A and C lines. The phase sequence is ABC. If the wattmeter with its current coil in Aphase line reads zero, then the power factor of the 3phase load will be  A) Zero lagging  B) Zero leading  C) 0.5 lagging  D) 0.5 leading  View Answer   Answer : 0.5 lagging

 