In an amplitude modulation, a modulating signal having amplitude of X Volt is superimposed with a carrier signal of amplitude Y Volt in first case. Then, in second case, the same modulating signal is superimposed with different carrier signal of amplitude 2Y Volt. The ratio of modulation index in the two cases respectively will be :

Given below are two statements : Statement I : For transmitting a signal, size of antenna ( $l$ ) should be comparable to wavelength of signal (at least $l=\frac{\lambda }{4}$ in dimension) Statement II: In amplitude modulation, amplitude of carrier wave remains constant (unchanged). In the light of the above statements, choose the most appropriate answer from the options given below

Which of the following frequencies does not belong to FM broadcast ?

The amplitude of $$15\sin (1000\pi \mathrm{t})$$ is modulated by $$10\sin (4\pi \mathrm{t})$$ signal. The amplitude modulated signal contains frequency (ies) of A. $$500\mathrm{Hz}$$ B. $$2\mathrm{Hz}$$ C. $$250\mathrm{Hz}$$ D. $$498\mathrm{Hz}$$ E. $$502\mathrm{Hz}$$ Choose the correct answer from the options given below:

Match List I with List II: .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; overflow:hidden;padding:10px 5px;word-break:normal;} .tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;} .tg .tg-0pky{border-color:inherit;text-align:left;vertical-align:top} List I List II A. Attenuation I. Combination of a receiver and transmitter. B. Transducer II. process of retrieval of information from the carrier wave at receiver C. Demodulation III. converts one form of energy into another D. quad Repeater IV. Loss of strength of a signal while propagating through a medium. Choose the correct answer from the options given below:

A sinusoidal carrier voltage is amplitude modulated. The resultant amplitude modulated wave has maximum and minimum amplitude of $$120\mathrm{V}$$ and $$80\mathrm{V}$$ respectively. The amplitude of each sideband is :

The modulation index for an A.M. wave having maximum and minimum peak-to-peak voltages of 14 mV and 6 mV respectively is-

If the height of transmitting and receiving antennas are 80 m each, the maximum line of sight distance will be: Given : Earth's radius $$=6.4\times 10^6$$ m

Match List I with List II .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; overflow:hidden;padding:10px 5px;word-break:normal;} .tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;} .tg .tg-c3ow{border-color:inherit;text-align:center;vertical-align:top} .tg .tg-7btt{border-color:inherit;font-weight:bold;text-align:center;vertical-align:top} .tg .tg-0pky{border-color:inherit;text-align:left;vertical-align:top} List I List II A. Troposphere I. Approximate 65-75 km over Earth's surface B. E-Part of Stratosphere II. Approximate 300 km over Earth's surface C. F$${}_2$$-Part of Thermosphere III. Approximate 10 km over Earth's surface D. D-Part of Stratosphere IV. Approximate 100 km over Earth's surface Choose the correct answer from the options given below :

A message signal of frequency 5 kHz is used to modulate a carrier signal of frequency 2 MHz. The bandwidth for amplitude modulation is :

Match List I with List II .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; overflow:hidden;padding:10px 5px;word-break:normal;} .tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;} .tg .tg-c3ow{border-color:inherit;text-align:center;vertical-align:top} .tg .tg-7btt{border-color:inherit;font-weight:bold;text-align:center;vertical-align:top} .tg .tg-0pky{border-color:inherit;text-align:left;vertical-align:top} List-I List-II A. AM Broadcast I. 88-108 MHz B. FM Broadcast II. 540-1600 kHz C. Television III. 3.7-4.2 GHz D. Satellite Communication IV. 54MHz - 890MHz Choose the correct answer from the options given below :

A modulating signal is a square wave, as shown in the figure. If the carrier wave is given as $$\mathrm{c}(\mathrm{t})=2\sin (8\pi \mathrm{t})$$ volts, the modulation index is :

The height of transmitting antenna is $180\mathrm{m}$ and the height of the receiving antenna is $245\mathrm{m}$. The maximum distance between them for satisfactory communication in line of sight will be : (given $\mathrm{R}=6400\mathrm{km})$

To radiate EM signal of wavelength $$\lambda$$ with high efficiency, the antennas should have a minimum size equal to:

Match List - I with List - II .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; overflow:hidden;padding:10px 5px;word-break:normal;} .tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;} .tg .tg-baqh{text-align:center;vertical-align:top} .tg .tg-amwm{font-weight:bold;text-align:center;vertical-align:top} .tg .tg-0lax{text-align:left;vertical-align:top} List - I (Layer of atmosphere) List - II (Approximate height over earth's surface) (A) $${\mathrm{F}}_1$$ - Layer (I) 10 km (B) $$\mathrm{D}$$ - Layer (II) 170 - 190 km (C) Troposphere (III) 100 km (D) $$\mathrm{E}$$ - Layer (IV) 65 - 75 km Choose the correct answer from the options given below:

The amplitude of $$15\sin (1000\pi \mathrm{t})$$ is modulated by $$10\sin (4\pi \mathrm{t})$$ signal. The amplitude modulated signal contains frequencies of A. $$500\mathrm{Hz}$$ B. $$2\mathrm{Hz}$$ C. $$250\mathrm{Hz}$$ D. $$498\mathrm{Hz}$$ E. $$502\mathrm{Hz}$$ Choose the correct answer from the options given below:

In satellite communication, the uplink frequency band used is :

A transmitting antenna is kept on the surface of the earth. The minimum height of receiving antenna required to receive the signal in line of sight at $$4\mathrm{km}$$ distance from it is $$x\times 10^{-2}\mathrm{m}$$. The value of $$x$$ is __________. (Let, radius of earth $$\mathrm{R}=6400\mathrm{km}$$ )

A message signal of frequency $$3\mathrm{kHz}$$ is used to modulate a carrier signal of frequency $$1.5\mathrm{MHz}$$. The bandwidth of the amplitude modulated wave is

A carrier wave of amplitude 15 V is modulated by a sinusoidal base band signal of magnitude 3 V. The ratio of maximum amplitude to minimum amplitude in an amplitude modulated wave is