
UPSC_Exams > UPSC_Indian_Engineering_Services_Answer > UPSC_IES_EC_2014_Answer_Key_Question_par 1) A periodic function satisfies Dirichlet's conditions. This implies that the function  A) is nonlinear  B) is not absolutely integrable  C) guarantees that Fourier series representation of the function exists  D) has infinite number of maxima and minima within a period  View Answer   Answer : guarantees that Fourier series representation of the function exists

2) Consider Fourier representation of continuous and discretetime systems. The complex exponentials (ie., signals), which arise in such representation, have  A) same properties always  B) different properties always  C) nonspecific properties  D) mostly same properties  View Answer   Answer : same properties always

3) If a dipole antenna has a radiation resistance of 73 ?, the loss resistance of 7 ? and the power gam is 16, then the directivity is  A) 17.53 dB  B) 24.7 dB  C) 40 dB  D) 14.6 dB  View Answer   Answer : 14.6 dB

4) An LTI system is causal if and only if  A) h(t) = 0 for t < 0  B) h(t) is finite for 0  C) h(t) is finite for t < 0  D) h(t) is nonzero for all t  View Answer   Answer : h(t) = 0 for t < 0

5) Let u[n] be the unitstep signal and x[n]=(^{1}⁄_{2})^{n} u[n] + (^{1}⁄_{3})^{n} u[n] The region of convergence of ztransform of x[n] is  A) z>1⁄3  B) 1 ⁄ 3 < z < 1⁄2  C) z>1⁄2  D) z<1⁄2  View Answer   Answer : z>1⁄2

6) If the ztransform of a sequence x[n] = {1,1,1,1} is X(z), then the value of X(1 ⁄2) is  A) 9  B) 1.875  C) 1.125  D) 15  View Answer   Answer : 1.125

7) If the ztransform of a system is given by H(z) =^{?+z1}⁄^{1+?z1} where ? is realvalued, ? ?, then the system is  A) a lowpass filter  B) a bandpass filter  C) an allpass filter  D) a highpass filter  View Answer   Answer : a lowpass filter

8) Consider a discrete random variable assuming finitely many values. The cumulative distribution function of such a random variable is  A) nonincreasing function  B) nondecreasing function with finitely many discontinuities and assuming values less than one  C) nondecreasing function without discontinuities  D) nondecreasing function assuming values larger than one  View Answer   Answer : nondecreasing function with finitely many discontinuities and assuming values less than one

9) A continuous random variable X has uncountable many values in the interval [a, b]. If C is a value in the interval [a, b], then P(X = C)  A) is zero  B) is strictly nonzero  C) depends on the limits {a, b}  D) is less than one, but nonzero  View Answer   Answer : is zero

10) In the case of a random variable dealing with nondeterministic signals  A) it is a function from space of outcomes to the real/complex numbers  B) it is a function with the probabilities of outcomes as random numbers  C) the values assumed by signals are always deterministic  D) sometimes the events associated with random variable are deterministic  View Answer   Answer : it is a function from space of outcomes to the real/complex numbers

 