Description : The _______ technique uses M different carrier frequencies that are modulated by the source signal. At one moment, the sign modulates one carrier frequency; at the next moment, thesignal modulates another carrier frequency. A) FDM B) DSSS C) FHSS D) TDM
Last Answer : FHSS
Description : ________ are usedfor short-range communications such as those between a PC and aperipheral device. A) Radio waves B) Microwaves C) Infrared waves D) none of the above
Last Answer : Infrared waves
Description : _____ are used for cellular phone, satellite,and wireless LAN communications. A) Radio waves B) Microwaves C) Infrared waves D) none of the above
Last Answer : Microwaves
Description : Wireless transmission of signals can be done via ___________ a. radio waves b. microwaves c. infrared d. all of the mentioned
Last Answer : d. all of the mentioned
Description : …….are used for short-range communications such as those between a PC and aperipheral device. a. Radio waves b. None of These c. Microwaves d. Infrared waves
Last Answer : d. Infrared waves
Description : ……………are used for cellular phone, satellite, and wireless LAN communications. a. Microwaves b. Radio waves c. None of these d. Infrared waves
Last Answer : a. Microwaves
Description : Geodimeter is based on: (A) Propagation of modulated light waves (B) Propagation of infrared radiation (C) The visible light as carrier with frequency of the order of 5 × 1014 Hz (D) High frequency radio waves
Last Answer : Answer: Option A
Description : Radar transmits short pulses of high frequency called A. Infrared waves B. Radio waves C. Ultraviolet waves D. Sound waves
Last Answer : ANSWER: B
Description : Which wave has the highest frequency? w) microwaves x) infrared waves y) ultraviolet waves z) radio waves
Last Answer : ANSWER: Y -- ULTRAVIOLET WAVES
Description : In TDM, the transmissionrate of the multiplexed path isusually_______ thesum of thetransmission rates of thesignal sources. A) greater than B) less than C) equal to D) not related to
Last Answer : greater than
Description : ______ finds the value of thesignal amplitudefor eachsample; ____ finds the change from the previous sample. A) DM; PCM B) PCM; DM C) DM; CM D) none of the abov
Last Answer : PCM; DM
Description : When propagationspeed is multiplied by propagation time, we get the ________. A) throughput B) wavelength of thesignal C) distortionfactor D) distancea signal or bit has traveled
Last Answer : distancea signal or bit has traveled
Description : What frequency range is used for FM radio transmission? A. Very Low Frequency : 3 kHz to 30. kHz B. Low Frequency :30 kHz to 300 kHz C. High Frequency :3 MHz to 30 MHz D. Very High Frequency : 30 MHz to 300 MHz E. None of the above
Last Answer : Very High Frequency : 30 MHz to 300 MHz
Description : What Infrared rays are electromagnet waves that are longer than radio waves but shorter than visible light rays true of false?
Last Answer : Need answer
Description : For sending sound waves at large distance, which waves are used? A. Infrared waves B. Radio waves C. Light waves D. X-waves
Description : Any energy which radiates in the form of radio waves, infrared waves, light waves, x-rays, etc. A. Radiant energy B. Electromagnetic C. Heat D. Ultraviolet
Last Answer : B. Electromagnetic
Description : Fiber optics posses following properties __________ a) Immune electromagnetic interference b) Very less signal attenuation c) Very hard to tap d) All of the mentioned
Last Answer : d) All of the mentioned
Description : Which of the following is an advantage to using fiber optics data transmission? a. resistance to data theft b. fast data transmission rate c. low noise level d. all of above
Last Answer : fast data transmission rate
Description : ________ generates light beam at a specific visible frequency. A. Glass fiber B. Infrared C. Light waves D. Laser
Last Answer : D. Laser
Description : Before data can be transmitted, they must be transformed to________. A) periodic signals B) electromagnetic signals C) aperiodic signals D) low-frequency sine waves
Last Answer : electromagnetic signals
Description : Which of the following types radiations is absorbed by the upper layer of the atmosphere? A. Radio-waves B. Infrared C. Visible D. Ultraviolet
Description : Which type of radiations are absorbed by the upper layer of the atmosphere? (1) Radio-waves (2) Infrared (3) Visible (4) Ultraviolet
Last Answer : (4) Ultraviolet Explanation: The Troposphere is the layer where the weather happens. Above this layer is the Stratosphere and in between them is the Ozone layer that absorbs the sun's ... . Above the Stratosphere is the Mesosphere, the Thermosphere including the Ionosphere - and the Exosphere.
Description : What do radioactive substances emit? (1) Radio waves (2) Infrared waves (3) Ultraviolet waves (4) α, β and γ rays
Last Answer : (4) α, β and γ rays Explanation: Of the three main types of radiation given off during radioactive decay, two are particles and one is energy; scientists call them alpha, beta and gamma after the first three letters of the Greek alphabet.
Description : Which of the following waves cannot be polarized? (1) Radio (2) Ultra violet (3) Infrared (4) Ultrasonic
Last Answer : (4) Ultrasonic Explanation: Only transverse waves (such as radio, ultraviolet and infrared waves) can be polarized since their vibrations can potentially occur in all directions perpendicular to the direction of travel. It is therefore possible to confine the vibrations to a single plane.
Description : The ozone layer protects us from - (1) Ultra violet rays (2) Radio waves (3) Visual radiation (4) Infrared radiation
Last Answer : (1) Ultra violet rays Explanation: The ozone layer acts as a filter for the shorter wavelength and highly hazardous ultraviolet radiation (UVR) from the sun, protecting life on Earth from its potentially harmful effects.
Description : Waves that are required for long distance wireless communication are – (1) Infrared rays (2) Ultraviolet rays (3) Radio waves (4) Microwaves
Last Answer : (3) Radio waves Explanation: Wireless communication is the transfer of information between two or more points that are not connected by an electrical conductor. With radio waves distances can be short ... , or as far as thousands or even millions of kilometres for deep-space radio communications.
Description : The principle used in radar is the same as that of Sonar. In radar we use radio waves ; whereas in sonar we use ? A. red waves B. Infrared waves C. Ultrasonic (Answer) D. super sonic E. None of these
Last Answer : C. Ultrasonic (Answer)
Description : Which type of radiations are absorbed by the upper layer of the atmosphere? (1) Radio-waves (2)Infrared (3) Visible (4) Ultraviolet
Last Answer : Ultraviolet
Description : Which of the following waves cannot be polarised? (1) Radio (2) Ultra violet (3) Infrared (4) Ultrasonic
Last Answer : Ultrasonic
Description : Waves that are required for long distance wireless communication are (1) Infrared rays (2) Ultraviolet rays (3) Radio waves (4) Microwaves
Last Answer : Radio waves
Description : Infrared range for fiber optics ∙ a. 400 – 700 nm ∙ b. 700 – 1200 nm ∙ c. 300 – 2000 nm ∙ d. 400 – 7000 nm
Last Answer : b. 700 – 1200 nm
Description : Radio waves are _________. A) omnidirectional B) unidirectional C) bidirectional D) none of the above
Last Answer : omnidirectional
Description : The types of Unguided transmission channel or media used for LAN are __. A. Twisted Pair Cables B. Coaxial Cables C. Radio Waves D. All the above
Last Answer : C. Radio Waves
Description : Which of hte following is considered a broad band communication channel? a. coaxial cable b. fiber optics cable c. microwave circuits d. all of above
Last Answer : all of above
Description : Which of the following performs modulation and demodulation? a. fiber optics b. satellite c. coaxial cable d. modem e. none of the above
Last Answer : modem
Description : Which of the following performs modulation and demodulation? a. fiber optics b. satellite c. coaxial cable d. Modem
Last Answer : d. Modem
Description : To measure the speed of an approaching car a police officer shines – (1) light waves on it (2) microwaves on it (3) radio waves on it (4) ultra high frequency waves on it
Last Answer : (3) radio waves on it Explanation: Radar, which stands for radio detection and ranging, is a system that uses reflected radio waves to detect objects and measure their distance and speed. For example, police use radar to calculate the speed of cars.
Description : To measure the speed of an approaching car a police officer shines (1) light waves on it (2) microwaves on it (3) radio waves on it (4) ultra high frequency waves on it
Last Answer : radio waves on it
Description : Which one of the following frequency regions is a part of sun's radiation? (A) Ultraviolet frequency region (B) Infrared frequency region (C) Radio frequency region (D) All of these
Last Answer : Answer: Option D
Description : Pick out the wrong statement (A) The concentric atmosphere layer just above troposphere is called stratosphere, which is rich in ozone (B) Mesosphere is characterised by very low atmospheric ... radio waves used in the long distance radio communication are reflected back to earth by stratosphere
Last Answer : (D) The radio waves used in the long distance radio communication are reflected back to earth by stratosphere
Description : Given two sine waves A and B, if the frequency of A is twicethat of B, thenthe period of B is ________ thatof A. A) one-half B) twice C) the sameas D) indeterminate from
Last Answer : twice
Description : Band of light waves, that are too short to be seen by human eye. A. Visible B. Infrared C. Ultraviolet D. Amber
Last Answer : C. Ultraviolet
Description : Why are visible-light LEDs not used for fiber optics? ∙ a. It has high losses ∙ b. It has short wave ∙ c. It has low attenuation ∙ d. It has weak signal
Last Answer : ∙ a. It has high losses
Description : Given an AM radio signal with abandwidth of10 KHzand the highest-frequency component at 705 KHz, what is the frequency of the carrier signal? A) 700 KHz B) 705 KHz C) 710 KHz D) Cannot bedetermined from giveninformation
Last Answer : 700 KHz
Description : What does Sending out a pulse of high frequency radio waves?
Description : What Palindromes for Sending out a pulse of high frequency radio waves?
Last Answer : radar