Home
Class 11
PHYSICS
Statement-I : Electromagnetic waves with...

Statement-I : Electromagnetic waves with frequencies smaller than the critical frequency of ionosphere cannot be used for communication using sky wave propagation
Statement-II : The refractive index of the ionosphere becomes very high for frequency.

A

Statetment-I is True, Statement-II is True , Statement-II is a correct explanation for Statement-I

B

Statement-I is True, Statement-II is True , Statement-II is NOT a correct explanation for Statement-I

C

Statement-I is True, Statement-II is False

D

Statement-I is False, Statement-II is True

Text Solution

Verified by Experts

The correct Answer is:
D
Promotional Banner

Topper's Solved these Questions

  • SEMICONDUCTORS

    ALLEN|Exercise Part-3(Exercise-4)|51 Videos
  • SEMICONDUCTORS

    ALLEN|Exercise Part-3(Exercise-2)|49 Videos
  • PHYSICAL WORLD, UNITS AND DIMENSIONS & ERRORS IN MEASUREMENT

    ALLEN|Exercise EXERCISE-IV|8 Videos
  • WAVES AND OSCILLATIONS

    ALLEN|Exercise Part-1(Exercise-05)[B]|42 Videos

Similar Questions

Explore conceptually related problems

Statement-1 : Electromagnetic waves with frequencies smaller than the critical frequency of ionosphere cannot be used for communications using sky wave propagation. Statement-2: The refractive index of the ionosphere becomes very high for frequenceis higher than the criritcal frequency.

Electromagnetic waves with frequency greater than the critical frequency of ionosphere cannot be used for communication using sky wave propagation, because:

Assertion : Electromagentic waves with frequencies more than the cirtical frequency of ionosphere cannot be used for communication using sky wave propagation. Reason : The refractive index of the ionosphere becomes very high for frequencies higher than the critical frequency .

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

Statement-1: Communication in UHF/VHF regions can be established by space wave or tropospheric wave. Statement-2 : The refractive index of the ionosphere becomes very high for frequencies higher than the critical frequency.

Electromagnetic waves of frequency ……. are reflected from ionosphere.

The electromagnetic waves of frequency range 100 to 300 Hz are used in

Among the follwing frequencies one will be suitable for beyond-the horizon communication using sky waves is

Which of the following frequencies will be suitable for beyond the horizon communication using sky waves?

ALLEN-SEMICONDUCTORS-Part-3(Exercise-3)
  1. Assertion: The television broadcasting becomes weaker with increasing ...

    Text Solution

    |

  2. Assertion: The Microwave propagation is better than the sky wave propa...

    Text Solution

    |

  3. Statement-I : Semiconductors do not obey Ohm's law Statement-II : El...

    Text Solution

    |

  4. Statement-I : Germanium is preferred over silicon for making semicondu...

    Text Solution

    |

  5. Assertion : p-n junction diode can be used even at ultra high frequenc...

    Text Solution

    |

  6. Statement-I : A p-n junction with reverse bias can be used as a photod...

    Text Solution

    |

  7. Assertion: NAND or NOR gates are called digital building blocks. Rea...

    Text Solution

    |

  8. Assertion: Two P-N junction diodes placed back to back, will work as a...

    Text Solution

    |

  9. Statement-I : When base region has larger width, the collector current...

    Text Solution

    |

  10. Statement-I : For faster action, n-p-n transistor is used Statement-...

    Text Solution

    |

  11. Statement-I : To be used as amplifier, the transistor in the common em...

    Text Solution

    |

  12. Statement-I : Many channels get allowed when transmission frequency is...

    Text Solution

    |

  13. Statement-I : Optical fibres are free from electromagnetic disturbance...

    Text Solution

    |

  14. Statement-I : Diode lasers are used as optical sources in optical comm...

    Text Solution

    |

  15. Statement-I : Electromagnetic waves with frequencies smaller than the ...

    Text Solution

    |

  16. Assertion : In optical fibre, the diameter of the core is kept small. ...

    Text Solution

    |

  17. Statement-I : For the same antenna length, power radiated by short wav...

    Text Solution

    |

  18. Statemet-1: the electrical conductivity of earth's atmosphere increase...

    Text Solution

    |

  19. Assertion:- Optical communication system is more economical than other...

    Text Solution

    |

  20. Statement-I : A communication satellite is essentially a repeater in s...

    Text Solution

    |