
UPSC_Exams > UPSC_Indian_Engineering_Services_Answer > UPSC_IES_EC_2014_Answer_Key_Question_par 1) Consider an LTI system representing a passive electrical network. If the input is a sinusoidal signal, then the steadystate output of the network is  A) sinusoidal with the same amplitude, frequency and phase  B) sinusoidal with the same frequency, but possibly different amplitude and phase  C) nonsinusoidal  D) sinusoidal with a different frequency  View Answer   Answer : sinusoidal with the same frequency, but possibly different amplitude and phase

2) A series RL circuit (R = 4? and L = 0.01 H) is excited by a voltage (in volt) v(t) = 283sin(300t + 90°). The current in the circuit will be  A) 40sin(300r + 53.1°) A  B) 40 sin 53.1° A  C) 40 ?2 sin(300r + 53.1°) A  D) 40 ?2 sin 53.1°A  View Answer   Answer : 40 ?2 sin(300r + 53.1°) A

3) An inductor L and 5 ? and 10 ? resistors are all connected in series across a voltage source v(t) = 50cos ?t volt. If the power consumed by the 5 ? resistor is 10 W, then the power factor of the circuit is  A) 0.3  B) 0.4  C) 0.6  D) 0.8  View Answer   Answer : 0.6

4) A graph in which at least one path (disregarding orientation) exists between any two nodes of the.graph is a  A) connected graph  B) directed graph  C) subgraph  D) fundamental graph  View Answer   Answer : connected graph

5) If Q_{t} and Q_{l} be the submatrices of Q_{f} (fundamental cutset matrix) corresponding to twigs and links of a connected graph respectively, then  1) Q_{t} is an identity matrix  2) Q_{l} is a rectangular matrix  3) Q_{f} is of rank (n  1)  4)   A) 1 and 2 only  B) 1 and 3 only  C) 2 and 3 only  D) 1, 2 and 3  View Answer   Answer : 1 and 3 only

6) Tellegen's theorem (as applicable to any lumped d.c. network, regardless of the elements being linear or nonlinear, timevarying or timeinvariant) implies that  A) sum of the voltage drops across each network element is equal to the total voltage applied to the network  B) sum of the powers taken by all elements, in the network, within the constraints imposed by KCL and KVL is zero  C) sum of the currents meeting at any node is not the same as the current in that mesh  D) it is applicable to a branch which is not coupled to other branches of the network  View Answer   Answer : sum of the powers taken by all elements, in the network, within the constraints imposed by KCL and KVL is zero

7) For the twoport network shown in the figure the transmission parameter C is   A) Z_{a}  B) 1+^{Za}⁄_{Zb}  C) Z_{b}  D) 1 ⁄Z_{b}  View Answer   Answer : 1 ⁄Z_{b}

9) The unit impulse response of a system is 4e^{t} +6e^{2t}. The step response of the same system for t ? 0 is Ae^{t} + Be^{2t} + C, where A, B and C are respectively  A) 4, 3 and +1  B) +4, 3 and 1  C) 4, 3 and 1  D) +4, 3 and +1  View Answer   Answer : +4, 3 and 1

10) The network function, H(s) is equal to  A) y(s)/x(s)  B) x(s)/y(s)  C) x(s)y(s)  D) 1/x(s)y(s)  View Answer   Answer : y(s)/x(s)

 