1. The conclusion regarding the time invariance of the system is
A. System is time-invariant
B. System is time variant
C. One more observation is required
D. Conclusion cannot be drawn from observation

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2. Consider the following statements (A) If S1 and S2 are linear, then S is linear (B) If S1 and S2 are nonlinear, then S is nonlinear (C) If S1 and S2 are causal, then S is causal (D) If S1 and S2 are time invariant, then S is time invariant True statements are :
A. A, B, C
B. B, C, D
C. A, C, D
D. all of these

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3.  Consider the following statements (A) If S and S2 are linear and time invariant, then interchanging their order does not change the system. (B) If S1 and S2 are linear and time varying, then interchanging their order does not change the system. True statements are :
A. Both and (B)
B. Only (A)
C. Only (B)
D. none of these

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4. The invertible system is
A. S1
B. S2
C. Both S1 and S2
D. None of these

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5. The transform of I'M) = e-4 u(t) is
A. G(t) g(f)
B. G(t) g*(f)
C. G(t) g(-f)
D. G(t) g*(-f)

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6. f(t) is a pulse defined as f(t) = I for 0 < I = 0 otherwise. The even part of f(t) is
A. -2 for 0
B. 1 for - 1
C. -2 for -1
D. 1 for - -2

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7. A real signal x[nl with Fourier transform X(e) has following property I. xinl = 0 for n > 0 2. x101 > 0 3. Im {X(ein) = sin 0 - sin 20) 4. -1 7 ix(ei)12 di/ = 3 2_ The signal x(n) is
A. 28[n] - 8[n + 1] - 8[n + 3]
B. 8[n] + 8[n + 1] - 8[n + 3]
C. 8[n] + 8[n + 1] - 8[n + 2]
D. 28[n] - 8[n + 1] - 8[n + 2]

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