{"id":24292,"date":"2020-02-24T17:52:15","date_gmt":"2020-02-24T12:22:15","guid":{"rendered":"https:\/\/kseebsolutions.guru\/?p=24292"},"modified":"2021-07-02T15:24:14","modified_gmt":"2021-07-02T09:54:14","slug":"2nd-puc-electronics-question-bank-chapter-7","status":"publish","type":"post","link":"https:\/\/kseebsolutions.guru\/2nd-puc-electronics-question-bank-chapter-7\/","title":{"rendered":"2nd PUC Electronics Question Bank Chapter 7 Wireless Communications"},"content":{"rendered":"

Students can Download 2nd PUC Electronics Chapter 7 Wireless Communications Questions and Answers, Notes Pdf, 2nd PUC Electronics Question Bank with Answers<\/a>\u00a0helps you to revise the complete Karnataka State Board Syllabus and score more marks in your examinations.<\/p>\n

Karnataka 2nd PUC Electronics Question Bank Chapter 7 Wireless Communications<\/h2>\n

2nd PUC Electronics Wireless Communications One Mark Questions and Answers<\/h3>\n

Question 1.
\nName any two paths that a radio signal can take through space.
\nAnswer:
\nThe paths that a radio signal can take through the space are:<\/p>\n

    \n
  • The ground wave<\/li>\n
  • The space wave<\/li>\n
  • The sky wave.<\/li>\n<\/ul>\n

    Question 2.
    \nName the two radio waves that propagate near to the surface of the earth.
    \nAnswer:<\/p>\n

      \n
    • The ground wave<\/li>\n
    • The space wave<\/li>\n<\/ul>\n

      Question 3.
      \nHow are ground waves polarized?
      \nAnswer:
      \nThe ground waves are vertically polarized.<\/p>\n

      \"2nd<\/p>\n

      Question 4.
      \nWhat is the frequency range of signal that propagate best over the surface of the earth?
      \nAnswer:
      \n30 kHz to 3 MHz.<\/p>\n

      Question 5.
      \nIdentify the radio waves which are refracted by the ionosphere.
      \nAnswer:
      \nVery high-frequency VHF (30 MHz to 300 MHz).<\/p>\n

      Question 6.
      \nMention the range of frequency signals that porpagate best through ionosphere.
      \nAnswer:
      \n30 kHz to 3 MHz.<\/p>\n

      Question 7.
      \nWhat is ionosphere?
      \nAnswer:
      \nIonosphere is the upper portion of the atmosphere, which absorbs large quantities of radiant energy from the sun and becomes heated and ionised.<\/p>\n

      Question 8.
      \nWhich layer of the ionosphere has the greatest effect on a radio signal?
      \nAnswer:
      \nF layer.<\/p>\n

      Question 9.
      \nWhich is the type of radio wave that propagates only over line-of-sight distance?
      \nAnswer:
      \nVHF (very high frequency) (30 MHz to 300MHz).<\/p>\n

      \"2nd<\/p>\n

      Question 10.
      \nWhat is fading?
      \nAnswer:
      \nFading is the fluctuation in the strength of the radio signal.<\/p>\n

      Question 11.
      \nDefine skip distance.
      \nAnswer:
      \nSkip distance is the minimum distance measured between transmitting antenna and the first receiving antenna measured along the surface of the earth after propagation through the ionosphere.<\/p>\n

      Question 12.
      \nDefine skip zone.
      \nAnswer:
      \nSkip zone or silent zone is the region around the receiving antenna, within the skip distance, where neither the ground wave nor sky wave is present.<\/p>\n

      Question 13.
      \nDefine critical angle.
      \nAnswer:
      \nCritical angle for a given layer is the maximum angle of incidence of a radio wave under ionospheric propagation that gets returned to the earth.<\/p>\n

      Question 14.
      \nDefine critical frequency.
      \nAnswer:
      \nCritical frequency for a given layer is the highest frequency of a beamed radio wave that will be returned to the earth.<\/p>\n

      Question 15.
      \nDefine electrical noise.
      \nAnswer:
      \nNoise is any unwanted electrical energy which interferes with the required signal.<\/p>\n

      Question 16.
      \nDefine signal to noise ratio.
      \nAnswer:
      \nSignal to noise ratio is the ratio of signal power to noise power.<\/p>\n

      \"2nd<\/p>\n

      Question 17.
      \nDefine noise ratio.
      \nAnswer:
      \nNoise ratio is the ratio of signal to noise ratio at the input to the signal to noise ratio at the output of the system.<\/p>\n

      Question 18.
      \nDefine noise figure.
      \nAnswer:
      \nNoise figure is the noise ratio expressed in decibel.<\/p>\n

      Question 19.
      \nMention the frequency of radio waves.
      \nAnswer:
      \n104<\/sup> to 1014<\/sup> Hz.<\/p>\n

      Question 20.
      \nDefine single hop distance.
      \nAnswer:
      \nSingle hop distance is the maximum distance between transmitting antenna to first receiving antenna measured along the surface of the earth after propagation through the ionosphere.<\/p>\n

      2nd PUC Electronics Wireless Communications Two Marks Questions and Answers<\/h3>\n

      Question 21.
      \nDraw the block diagram of basic electronic communication system.
      \nAnswer:
      \n\"2nd<\/p>\n

      Question 22.
      \nWrite a short note on noise.
      \nAnswer:
      \nNoise is any unwanted electrical energy which interferes with the correct reception and reproduction of the required signal. Noise may be internal or external. Noise cannot be eliminated but can be minimized. Noise can be measured in a system using the parameters like signal to noise ratio, noise figure etc.<\/p>\n

      \"2nd<\/p>\n

      Question 23.
      \nMention the types of radio propagation.
      \nAnswer:<\/p>\n

        \n
      • Ground waves.<\/li>\n
      • Space waves.<\/li>\n
      • Sky waves.<\/li>\n<\/ul>\n

        Question 24.
        \nMention the layers of ionosphere.
        \nAnswer:<\/p>\n

          \n
        • l.D layer<\/li>\n
        • E layer.<\/li>\n
        • F layer.<\/li>\n<\/ul>\n

          Question 25.
          \nWrite a note on single hop distance.
          \nAnswer:
          \nThe single hop distance is the maximum distance between the transmitting antenna to first receiving antenna measured along the surface of the earth after ionospheric propagation. For F2<\/sub> layer, maximum single hop distance is 4000 km. As the average circumference of the earth is 20,000 km, the signal needs to undergo multiple hops, if it has to achieve round the globe communication.<\/p>\n

          Question 26.
          \nWhat is fading? Explain.
          \nAnswer:
          \nFading is fluctuations in the strength of radio signal. Fading occurs due to absorption in the layers of the atmosphere, loss during refraction, loss due to scattering of signals. Fading can be reduced by using repeater stations which boost up the signal strength satisfactorily to reach the receiving
          \n<\/span><\/p>\n

          2nd PUC Electronics Wireless Communications Three Marks Questions and Answers<\/h3>\n

          Question 27.
          \nWrite frequency allocation table for different communication systems.
          \nAnswer:<\/p>\n\n\n\n\n\n\n\n\n\n\n\n
          Frequency<\/strong><\/td>\nName of frequency band<\/strong><\/td>\nUses<\/strong><\/td>\n<\/tr>\n
          3-30 kHz<\/td>\n(VLF) Very low frequency<\/td>\nLong distance communication<\/td>\n<\/tr>\n
          30 kHz-300 kHz<\/td>\nLow frequency (LF)<\/td>\nNavigation services<\/td>\n<\/tr>\n
          300 kHz-3 MHz<\/td>\nMedium frequency (MF)<\/td>\nRadio broadcasting. Police walkie-talkie.<\/td>\n<\/tr>\n
          3 MHz-30 MHz<\/td>\nHigh Frequency (HF)<\/td>\nTelephone,aviation.<\/td>\n<\/tr>\n
          30 MHz-300 MHz<\/td>\nVery high frequency (VHF)<\/td>\nRadar, TV, Fm broadcasting.<\/td>\n<\/tr>\n
          300 MHz-3 GHz<\/td>\nUltra high Frequency (UHF)<\/td>\nTV, Radar, Aviation<\/td>\n<\/tr>\n
          3 GHz-30 GHz<\/td>\nSuper high frequency (SHF)<\/td>\nSatellite communication Radar.<\/td>\n<\/tr>\n
          30 GHz-300 GHz<\/td>\nExtreme high frequency (EHF)<\/td>\nSpecial purpose communication.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

          \"2nd<\/p>\n

          Question 28.
          \nExplain in brief ground wave propagation.
          \nAnswer:
          \nGround waves are the waves transmitted along or reflected from the surface of the earth. These can exist when the transmitting and receiving antennas are close to the surface of the earth.<\/p>\n

          The ground wave is vertically polarised and will transmit most effectively at a frequency less than 2 MHZ<\/sub>. The AM broad cast signals travel as ground waves. The strength of the ground wave is reduced due to energy absorption by the earths surface.<\/p>\n

          Question 29.
          \nWith relevant diagram, explain ionospheric propagation.
          \nAnswer:
          \nUltraviolet radiation from the sun cause the upper atmosphere to ionize i.e. to become electrically charged. Hence a thick layer of ions formed at heights of 50 km to 400km. The ionosphere supports MF and HF wave propagation.
          \nIts three layers are:<\/p>\n

          D layer: It is at a height of 70 km and has an average thickness of 10 km. It disappears in the night time. It reflects VLF and LF waves and absorbs MF and HF waves.<\/p>\n

          E layer: It is at a height of 100 km with a thickness of 25 km. This layer disappears at night. It helps in MF and HF wave propagation.<\/p>\n

          F layer: It is at a height of 150 km and extends upto 400 km. This layer exists during both day and night time. During day time, it splits into two layers F, and F2<\/sub>, and combines to form a single F layer during night time.<\/p>\n\n\n\n\n\n\n\n
          F2<\/sub> region. 250-400 km.<\/td>\n<\/tr>\n
          F1<\/sub> region. 160-250 km.<\/td>\n<\/tr>\n
          E region. 95-130 km<\/td>\n<\/tr>\n
          D region. 50-95 km.<\/td>\n<\/tr>\n
          Troposphere Earth.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

          \"2nd<\/p>\n

          Question 30.
          \nExplain the concept of space wave propagation.
          \nAnswer:
          \nSpace waves are the waves that travel from the transmitting to receiving antenna in the earths troposphere (first 18 km from earths surface). Space waves have two components.One of them is line of sight ray which travels directly from transmitting to receiving antenna.The other is ground reflected wave, which reaches the receiver due to reflection from the surface of the earth. Radio transmission at frequencies above 30 MHz, TV, FM, radar use space wave propagation.<\/p>\n

          2nd PUC Electronics Wireless Communications Five Marks Questions and Answers<\/h3>\n

          Question 31.
          \nDraw the block diagram of an electronic communication system and explain the function of each block in brief.
          \nAnswer:
          \n\"2nd<\/p>\n

          Question 32.
          \nDefine important terms used in ionospheric propagation. Define single hop distance. Answer:
          \nIonosphere is the layer of ions at a height of 50 km to 400 km formed due ionisation by ultraviolet radiations from the sun.<\/p>\n

          D layer of ionosphere is at a height of 70 km which has a thickness of 10 km. It disappears at night and reflects VLF and LF waves.<\/p>\n

          E layer of ionosphere is at a height of 100 km and has a thickness of 25 km. It disappears at night and helps MF and HF wave propagation.<\/p>\n

          F layer is at a height of 150 km and extends upto 400 km. It remains during both day and night . time. During day time, it splits into two layers Fj and F2<\/sub> and combines to form a single F layer during night time.<\/p>\n

          F1<\/sub> layer or kennelly-Heaviside layer is at a height of 200 km with a thickness of 20 km. Itreflects HF waves.<\/p>\n

          F2<\/sub> layer or Appleton layer is at a height of 300 km and has a thickness of 20 km. It is usefull in HF wave propagation.<\/p>\n

           <\/p>\n","protected":false},"excerpt":{"rendered":"

          Students can Download 2nd PUC Electronics Chapter 7 Wireless Communications Questions and Answers, Notes Pdf, 2nd PUC Electronics Question Bank with Answers\u00a0helps you to revise the complete Karnataka State Board Syllabus and score more marks in your examinations. Karnataka 2nd PUC Electronics Question Bank Chapter 7 Wireless Communications 2nd PUC Electronics Wireless Communications One Mark …<\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[82],"tags":[],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts\/24292"}],"collection":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/comments?post=24292"}],"version-history":[{"count":0,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/posts\/24292\/revisions"}],"wp:attachment":[{"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/media?parent=24292"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/categories?post=24292"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kseebsolutions.guru\/wp-json\/wp\/v2\/tags?post=24292"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}