R4RIN – MCQs, Mock Tests | IIT JEE IIT JEE Principles Of Communication set-2

The dc voltage applied at each station in case of coaxial cables is

1. 1400 V
2. 1300 V
3. 1350 V
4. 1250 V

✅ Correct Answer: 3

The maximum frequency at which coaxial cable operates

1. 2500 mc/s
2. 2000 mc/s
3. 3000 mc/s
4. 300 mc/s

✅ Correct Answer: 3

Process of sending and receiving the information with the help of some suitable system is called

1. Communication
2. Tranxmission
3. Fax
4. Modem

✅ Correct Answer: 1

Which of the following pair belongs to the same communication system

1. Telephony Fax
2. Telegraphy E-mail
3. Teleprinting
4. Communication satellite Telemetry Mobile Phone

✅ Correct Answer: 4

Modem is a device which performs

1. Modulation
2. Demodulation
3. Rectification
4. Modulation and demodulation

✅ Correct Answer: 4

A certain transmitter radiates 9 kW of power with carrier unmodulated and 10.125 kW when the carrier is modulated. The modulation index is

1. 60%
2. 55%
3. 40%
4. 50%

✅ Correct Answer: 4

The satellite that is used in ship to shore and shore to ship communication is

1. Comsat
2. Marisat
3. Telstar
4. Intelstar

✅ Correct Answer: 3

Electronic transmission of a document to a distant place via telephone line is called

1. Fax
2. Modem
3. E-mail
4. Telephone

✅ Correct Answer: 1

Which of the following is use for analogue to digital conversion ?

1. Amplitude modulation
2. Pulse code modulation
3. Frequency modulation
4. Phase modulation

✅ Correct Answer: 2

If the wavelength of the electromagnetic radiations is doubled frequency of the electromagnetic radiations will be

1. same as earlier
2. half the earlier
3. double the earlier
4. four times the earlier

✅ Correct Answer: 2

The optical source is used to

1. convert electrical energy into optical energy
2. deted the signal
3. demodulate the electrical signal
4. All of the above

✅ Correct Answer: 1

The maximum usable frequency in F-layer with original frequency of 50 MHz will be

1. 181 MHz
2. 150 MHz
3. 250 MHz
4. 300 MHz

✅ Correct Answer: 1

The frequency of a wave propagating in D-region having refractive index is 0.5 is

1. 400 Kc/s
2. 300 Kc/s
3. 207.33 Kc/s
4. None of these

✅ Correct Answer: 3

For a FM wave the carrier is 160 MHz modulating frequency is 15 kHz and frequency deviation of 1 MHz if modulating frequency is doubled the band width will be

1. 5 MHz
2. 3 MHz
3. 2 MHz
4. 1 MHz

✅ Correct Answer: 3

If total power content of an AM wave is 2.64 kW at 80% modulation then power content of each side band are

1. 1.32 kW
2. 2.64 kW
3. 660 watt
4. 320 watt

✅ Correct Answer: 4

Total power content of an AM waves is 1500 watt. For a 100% modulation power content of carrier should be

1. 500 watt
2. 1000 watt
3. 1500 watt
4. None of these

✅ Correct Answer: 2

A charge having oscillating frequency 2 MHz. The wavelength will be None of these

1. 150 KM
2. 200 KM
3. 250 KM
4. None of these

✅ Correct Answer: 1

A band width of 15 MHz is available for transmission. If maximum signal frequency used for modulating the corrier is 15 kHz then low number of stations which can broadcast without any inference with each other ) in this band is

1. 300
2. 400
3. 457
4. 500

✅ Correct Answer: 4

The UHF band ranges from

1. 30 to 300 MHz
2. 30 to 3000 MHz
3. 20 to 2000 MHz
4. 30 to 300 KHz

✅ Correct Answer: 4

A sinusoidal carrier wave of frequency of 15 MHz is modulated by audio signal of frequency of 5 KHz then upper frequency component of the resultant modulated wave is

1. 15 MHz
2. 10 MHz
3. 15.005 MHz
4. 14.995 MHz

✅ Correct Answer: 3

For a FM wave the carrier is 160 MHz modulating frequency is 15 kHz and frequency deviation of 1 MHz. The band width required is

1. 2 MHz
2. 1 MHz
3. 20 KHz
4. 10 MHz

✅ Correct Answer: 1

The glass of optical fibre has refractive index 1.6 and is clad with another glass of refractive index 1.52. The numerical aperture will be

1. 0.499
2. 0.459
3. 0.0625
4. 0.352

✅ Correct Answer: 1

A modulated wave has maximum amplitude of 750 mV and minimum amplitude of 250 mV. Then percentage modulation is

1. 33%
2. 50%
3. 75%
4. 100%

✅ Correct Answer: 2

If a carrier wave of amplitude to mV is modulated by an audio signal of amplitude 2 mV then amplitude of LSF and USF is given by

1. 0.2 mV
2. 0.5 mV
3. 1 mV
4. 2 mV

✅ Correct Answer: 3