17-03-2014, 10:13 AM
Electronics & Communication - Electronices Sample Questions
Q-8 A circuit has a resistance of 11 W, a coil of inductive reactance 120 W, and a
capacitor with a 120-W reactance, all connected in series with a 110-V, 60-Hz power
source. What is the potential difference across each circuit element?
A) (a) VR = 110 V, (b) VL = VC = 1.2 Kv
B) (a) VR = 120 V, (b) VL = VC = 2.4 kV
C) (a) VR = 4.8 V, (b) VL = VC = 0 kV
D) (a) VR = 5.0 V, (b) VL = VC = 8.0 V
Q-2 Applying DeMorgan's theorem to the expression , we get
A) (A+B)+C
B) A(B + C)
C) Both A & B
D) None of above
Q-4 Refer Below figure to Determine the resonant frequency...
A) 123.4 kHz
B) 61.7 kHz
C) 45.97 kHz
D) 23.1 kHz
Q-4 Express the decimal number 57 in binary.
A) 100101
B) 111010
C) 110010
D) 111001
Q-5 A vertical electric dipole antenna
a) radiates uniformly in all directions.
b) radiates uniformly in all horizontal directions, but more strongly in the vertical
direction.
c) radiates most strongly and uniformly in the horizontal directions
d) does not radiate in the horizontal directions
Q-6 A particle oscillates according to the equation y=5.0 cos 23 t, where y is in
centimeters. Find its frequency of oscillation and its position at t=0.15 s.
a) f = 23 Hz, y = -4.8 cm
B) f = 3.7 Hz, y = -5.0 cm
C) f = 3.7 Hz, y = -4.8 cm
D) f = 3.7 Hz, y = +4.8 cm
Q-7 A 10.0-μF capacitor is in series with a 40.0-W resistance, and the combination is
connected to a 110-V, 60.0-Hz line. Calculate (a) the capacitive reactance, (b) the
impedance of the circuit, © the current in the circuit, (d) the phase angle between current
and supply voltage
A) (a) 0.0038W (b) 305W © 0.415 A (d) voltage lags by 8.58°
B) (a) 266W (b) 269W © 0.409 A (d) voltage lags by 81.4°
C) (a) 16 kW (b) 72 kW © 2.75 A (d) voltage lags by 6.63°
D) (a) 2.6 kW (b) 262W © 0.256 MA (d) voltage leads by 81.4°
Q-8 A circuit has a resistance of 11 W, a coil of inductive reactance 120 W, and a
capacitor with a 120-W reactance, all connected in series with a 110-V, 60-Hz power
source. What is the potential difference across each circuit element?
A) (a) VR = 110 V, (b) VL = VC = 1.2 Kv
B) (a) VR = 120 V, (b) VL = VC = 2.4 kV
C) (a) VR = 4.8 V, (b) VL = VC = 0 kV
D) (a) VR = 5.0 V, (b) VL = VC = 8.0 V
Q-9 What is the primary function of multiplexing?
A ) To match the frequency range of a signal to a particular channel.
B ) To reduce the bandwidth of a signal.
C ) To select one radio channel from a wide range of transmitted channels.
D ) To allow a number of signals to make use of a single communications channel.
Q-10 A second step to further increase system capacity is a digital access method called
TDMA (Time Division Multiple Access). Using the same frequency channelization and
reuse as FDMA analog but adding a time sharing element, the effective capacity is:
A) Doubled
B) Tripled
C) Reduced by one third
D) Unchanged