A signal wave of frequency 12 kHZ is modulated with a carrier wave of frequency 2.51 MHz. The upper and lower side band frequencies are respectively

• 2512 kHz and 2508 kHz

• 2522 kHz and 2488 kHz

• 2502 kHz and 2498 kHz

• 2522 kHz and 2498 kHz

The range of frequencies allotted for FM radio is

• 88 to 108 kHz

• 88 to 108 MHz

• 47 to 230 kHz

• 47 to 230 MHz

If a radio receiver amplifies all the signal frequencies equally well, it is said to have high

• fidelity

• distortion

• sensibility

• sensitivity

A TV tower has a height of 100 m. What is the maximum distance up to which the TV transmission can be received (R = 8 × 10⁶ m) ?

• 34.77 km

• 32.70 km

• 40 km

• 40.70 km

Amplitude modulation has

• one carrier with infinite frequencies

• one carrier with two side band frequencies

• one carrier with high frequency

• one carrier

46.

The waves used for Line-of-Sight (LOS) communication is

• sound waves

• ground waves

• sky waves

• space waves

The process of superimposing message signal on high frequency carrier wave is called

• amplification

• demodulation

• transmission

• modulation

A basic communication system consists of

1. Transmitter
2. Information sources
3. User of information
4. Channel
5. Receiver

• ii, i, iv, v and iii

• i, ii, iii, iv and v

• ii, v, i, iv and iii

• ii, iv, i, iii and v

Two sources of sound placed close to each other, are emitting progressive waves given by
y₁ = 4sin 600π t and y₂ = 5 sin 608πt

An observer located near these two sources of sound will hear

•  4 beats per second  with intensity ratio 25: 16 between waxing and waning

• 8 beats per second with intensity ratio 25:16 between  waxing and waning

• 8 beats per second with intensity ratio 81:1 between waxing and waning

• 8 beats per second with intensity ratio 81:1 between waxing and waning

A source emits electromagnetic waves of wavelength 3m. One beam reaches the observer directly and other after reflection from a water surface, travelling 1.5 m extra distance and with an intensity reduced to 1/4 as compared to intensity due to the direct beam alone. The resultant intensity will be.

• (1/4) fold

• (3/4) fold

• (5/4) fold

• (9/4) fold