Arrange in ascending order of cut off
frequency (f_{c}) of the waveguides in the following modes as
An AC voltage source v = V_{o} sin cot is
connected across a parallel plate capacitor
'C'. The displacement current in the capacitor is equal to
Conduction current inThe connecting wires
= i
= CωV_{o} cos ωt .............. (I)
For a parallel plate capacitor of area 'A and plate separation 'd',
......................(ii)
Electric field (E) =
Also, D = Electric flux density
Now, displacement current (i_{d})
⇒
= CωV_{o} cos ωt ............ (iii)
From equation (i) and (iii) we have
i = i_{d}
A plane wave is characterized by The wave is
Skin depth at a frequency of 1.6 MHz inaluminium, σ = 38.2, μ_{r} = 1.
Skin depth
=
= 64.4 mm
An uniform sinusoidal plane wave in air hasthe following expression for electric field The frequency of operation will be
General expression,
⇒
Now, frequency =
⇒
A dipole antenna was radiating with some excitation in free space radiating a certain amount of the power. If this antenna is immersed in a lake where water is nonmagnetic and non-dissipative but has a dielectric constant of 81, the radiated power with the same excitation will
A dipole antenna of λ/8 length has anequivalent total loss resistance of 1.5ΩThe efficiency of the antenna is:
Match List-I (Laws) with List-II (Applica- tions) and select the correct answer:
List-I
A. Ampere's law
B. Biot's law
C. Coulomb's law
D. Gauss's law
List-II
To find the
force on a charge
force due to a current carrying
electric flux density at a point
magnetic flux density at a point
A signal m(t) is band limited upto 20 kHz is sampled at `f_{s}' kHz. An ideal LPF having cut off frequency 57 kHz is used to reconstruct the m(t). The minimum value of `f_{s}' required to reconstruct m(t) without distortion is,__________ kHz
For the distortion less reconstruction of m(t)
signal,
f_{s }- f_{m} ≥ 57 kHz
⇒ f_{s} ≥ 57 + f_{in}
⇒ f_{s} ≥ 77 kHz
An AM transmitter is to deliver a total power of 100 W to an antenna. The percentage modulation is to be 100%. The power contained in each sideband is
Which one of the following sequence is correct regarding bandwidth (BW) of various analog modulated system?
The nyquist sampling rate for the signal s(t) = 20 cos(50πt) . cos^{2}(150πt) is,
The maximum frequency component will be
= 150 + 25
= 175 Hz
∴ Nyquist sampling rate
= f_{s}
= 2 f_{m}
= 2 x 175Hz
= 350 samples/sec
The modulation index of an FM signal having a carrier swing of 100 kHz and modulating frequency of 8 kHz is
∴ Carrier swing = 2 x Δf
⇒ Δf = 50 kHz
Also, modulation index
∴
= 6.25
For the generation of an AM signal we have m(t) = cos (4π x 10^{4} t) and c(t) = 5 cos(2π x 10^{6} t) where m(t) represents message signal and c(t) represents carrier signal then what would be the relation between total power (P_{T}) and power contained in one of its side band (P_{s}) if the modulation index is 0.5?
∴
Let
∴
⇒ . .......(ii)
∴ From equation (ii)
⇒ P_{T} = 18 P_{s}
Percentage modulation of an AM wave having a power content of 8 kW at carrier frequency and 2 kW in each of its bands is given by
Given That
⇒ m= 1
∴ % modulation = 100%
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