Home
Class 11
PHYSICS
In burglar alarm, infrared beam of light...

In burglar alarm, infrared beam of light is used instead of visible light, because

A

work function of infrared ligth is low.

B

infrared lamps are cheap.

C

infrared beam can be concealed from the burglar.

D

frequency of infrared light is higher than frequency of visible light.

Text Solution

Verified by Experts

The correct Answer is:
C
Promotional Banner

Topper's Solved these Questions

  • ELECTRONS AND PHOTONS

    TARGET PUBLICATION|Exercise Critical thinking|22 Videos

  • ELECTRONS AND PHOTONS

    TARGET PUBLICATION|Exercise Competitive Thinking|78 Videos

  • COMMUNICATION SYSTEMS

    TARGET PUBLICATION|Exercise Evaluation Test|15 Videos

  • FORCE

    TARGET PUBLICATION|Exercise Evaluation Test|16 Videos

Similar Questions

Explore conceptually related problems

A quantum of visible light is called

The wavelength of visible light is

The path of a bean of light through smoke is visible because

Wavelength of visible light/PAR is

What is a divergent beam of light?

Red light is generally used to observe diffraction pattern from single slit. If blue light is used instead of red light, then diffraction pattern

Red light is generally used to observe diffraction pattern from single slit. If blue light is used instead of red light, then diffraction pattern.

In fog, photographs of the objects taken with infrared radiations are more clear than those obtained during visible light because

TARGET PUBLICATION-ELECTRONS AND PHOTONS-Evaluation Test
  1. In burglar alarm, infrared beam of light is used instead of visible li...

    Text Solution

    |

  2. Relation between the stopping potential V0 of a metal and the maximum ...

    Text Solution

    |

  3. Radiation of wavelength 120 nm ejects photoelectrons from a plate whos...

    Text Solution

    |

  4. A surface receives light of wavelength lambda1=450 nm, causing the eje...

    Text Solution

    |

  5. Assertion: Photons can exist at rest. Reason: Rest mass m0=msqrt(((1...

    Text Solution

    |

  6. When a monochromatic point source of light is at a distance of 0.2 m f...

    Text Solution

    |

  7. Assertion: Work function of a metal is 4 eV. The maximum wavelength of...

    Text Solution

    |

  8. Eye of an experimenter detects the green light (lambda =4000 Å) at 5xx...

    Text Solution

    |

  9. Photon having wavelength lambda = 3.5xx10^(-7)m and lambda = 5.4xx10^(...

    Text Solution

    |

  10. Illuminating a metal surface alternately with wavelengths lambda1 and ...

    Text Solution

    |

  11. A proton when accelerated through a potential difference of V volt has...

    Text Solution

    |

  12. The work function for the following metals is given Na: 2.75 eV, K:2.3...

    Text Solution

    |

  13. Assertion: Work function of a metal is proportional to maximum wavelen...

    Text Solution

    |

  14. The retarding potential for having zero photo - electron current

    Text Solution

    |

  15. A proton and an alpha-particle are accelerated through same potential ...

    Text Solution

    |

  16. Light of wavelength 3000 Å falls on a sensitive surface. If the surfac...

    Text Solution

    |

  17. The work function for aluminium is 4.125 eV. The cut-off wavelength fo...

    Text Solution

    |

  18. Two metallic plates P(collector) and Q (emitter) are separated by a di...

    Text Solution

    |

  19. Lights of two different frequencies whose photons have energies 1 eV a...

    Text Solution

    |

  20. When a metal surface is illuminated by a monochromatic light of wave-l...

    Text Solution

    |