Test: Electromagnetic & Analog Communications - 1 - Electronics and Communication Engineering (ECE) MCQ

Skin depth at a frequency of 1.6 MHz inaluminium, σ = 38.2, μ_r = 1.

An uniform sinusoidal plane wave in air hasthe following expression for electric field The frequency of operation will be

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

1. force on a charge

2. force due to a current carrying

3. electric flux density at a point

4. magnetic flux density at a point

A signal m(t) is band limited upto 20 kHz is sampled at `f<sub>s</sub>' 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

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) . cos²(150πt) is,

The modulation index of an FM signal having a carrier swing of 100 kHz and modulating frequency of 8 kHz is 

For the generation of an AM signal we have m(t) = cos (4π x 10⁴ t) and c(t) = 5 cos(2π x 10⁶ 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?

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