Mock Test

Wave motion

by Anish
Updated On:

Wave motion

Total Questions: 44

31. The waves are used in common TV remote control are: [R.A.S/R.T.S (PRE) 2018]

Correct Answer: (c) infrared rays
Solution:Infrared rays are commonly used in TV remote control.Remote control can be used to operate device such as television set DVD player or other appliances.

32. Which type of the electromagnetic radiation is used in the remote control of a television ? [U.P.P.C.S.(pre) 2002,10,13, U.P.U.D.A./L.D.A.(PRE) 2010]

Correct Answer: (a) infrared rays
Solution:Infrared rays are commonly used in TV remote control.Remote control can be used to operate device such as television set DVD player or other appliances.

33. Which electromagnetic radiation is used in the remote control of a television ? [Uttarakhand P.C.S. (PRE) 2013]

Correct Answer: (a) infrared rays
Solution:Infrared rays are commonly used in TV remote control.Remote control can be used to operate device such as television set DVD player or other appliances.

34. Which on of the following does a TV remote control unit use to operate a TV set ? [U.P.P.C.S.(MAINS) 2013, I.A.S. (PRE) 2000]

Correct Answer: (d) radio wave.
Solution:While most TV remotes actually use infrared radiation, which is a type of light wave, some older models or more advanced ones might utilize radio waves for communication with the TV. 

35. Waves used for telecommunication are - [U.P.P.C.S.(MAINS) 2013]

Correct Answer: (d) micro wave
Solution:The microwave are high-frequency signals in the 300 MHz to 300 GHz range . The signals can carry thousands of channels at the same time making it is very versatile communication system.

Microwave is often used for point to point telecommunication today microwave is employed by the telecommunication industry in the form of both terrestrial relays and satellite communication .

36. The process of superposition of any information on the radiowaves is named as : [Jharkhand P.C.S. (PRE) 2023]

Correct Answer: (b) modulation
Solution:The process of superimposing any information (audio or video messages ) on carrier radiowaves is called modulation .

37. Which is not true about FM (Frequency modulation ) radio ways ? [Chhattisgarh P.C.S.(PRE) 2021]

Correct Answer: (a) frequency range of frequency modulation is lower than that of amplitude modulation.
Solution:Edwin Howard Armstrong was an American electrical engineer who invented wideband frequency modulation (FM) radio. Armstrong presented his paper, "A Method of Reducing Disturbances in Radio Signaling by a System of Frequency Modulation", (which first described FM radio) before the New York, section of the Institute of Radio Engineers on November 6, 1935.

The paper was published in 1936 FM requires a wider signal bandwidth (and higher frequency range) than amplitude modulation (AM) by an equivalent. modulating signal, this also makes the signal more robust against noise and interference. In frequency modulation, the carrier amplitude and phase remains constant, but its frequency changes in accordance with the modulating signal.

38. FM broadcasting service uses the range of frequency bands between - [R.A.S/R.T.S (PRE) 2013]

Correct Answer: (d) 88-108 MHz
Solution:FM broadcasting service uses the range of frequency bands between 88 to 108 MHz. There is a number of band allocation used around the globe:
1. 87.5-108 MHz - It is the "standard" VHF FM band. The one which is most widely used around the globe.
2. 76-90 MHz- This VHF FM band is used in Japan.
3. 65.8-74.0 MHz- This VHF FM band is known as the OIRT band. It was used in Eastern Europe although few other countries such as Russia, Ukraine also use it

39. A radio station broadcast at a 30 metre band the frequency of the carrier wave transmitted by this station is :- [R.A.S./R.T.S (PRE) 1993]

Correct Answer: (c) 100 MHz
Solution:

According to formula n=C/l
[where n=frequency, c=speed of light; l=wavelength ]
n=3×10⁸/30=10×10⁶=10 MHz

40. A layer in earth atmosphere called ionosphere facilities radio communication. why ? [I.A.S. (PRE) 2011]

1. The presence of ozone causes the reflection of radio wave to earth.
2. Radio wave have a very long wavelength.
which of the statement given above is/are correct ?

Correct Answer: (d) neither 1 nor 2
Solution:Both the statement are incorrect in the context of the question radio wave have a long wavelength but the presence of electrical charged ions in ionosphere facilitates radio communication.

Anish

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