Electronics and Communication Engineering - Exam Questions Papers

11. 

A system with transfer function has an output for the input signal . Then, the system parameter 'p' is

A. 3
B.
C. 1
D.

Answer: Option B

Explanation:

|y(t)| = |M(ω)||x(t)|.

ω2 + p2 = ω2p2, 4 + p2 = 4p2

3p2 = 4, .


12. 

The current i(t), though a 10 Ω resistor in series with an inductance, is given by i(t) = 3 + 4 sin (10t + 45°) + 4 sin (300t + 60°) Amperes. The RMS value of the current and the power dissipated in the circuit are

A. 41 A, 410 W, respectively
B. 35 A, 350 W, respectively
C. 5 A, 250 W, respectively
D. 11 A, 1210 W, respectively

Answer: Option A

Explanation:

Irms = = 6.4

Power P = I2R = 25 x 10 = 41 x 10 = 410 W.


13. 

The differential equation for the current i(t) in the circuit of figure is

A.
B.
C.
D.

Answer: Option C

Explanation:

Apply KVL to the loop

Differentiate w.r.t. t

.


14. 

A transmitter radiates a power 20 KW and its base current is 18A. The radiation resistance of the antenna is

A. 1111 Ω
B. 900 Ω
C. 75 Ω
D. 62 Ω

Answer: Option D

Explanation:

.


15. 

e-2t is __________ .

A. energy signal
B. power signal
C. neither energy signal nor power signal
D. both energy and power signal

Answer: Option C

Explanation:

E = e-4tdt

which is infinity

Power of the signal

This is of ∞/∞ form, we make use of L' hospital rule

e-2t is neither an energy signal nor a power signal.