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General Knowledge :: Physics

  1. The bats can fly in the dark because

  2. A.

     They can see the objects in darkness

    B.

     They have weak legs and are likely to be attacked by predators

    C.

     They generate flashes of light

    D.

     They generate ultrasonic sound waves


  3. The device used for locating submerged objects under sea is.

  4. A.

     Sonar

    B.

     Radar

    C.

     Laser

    D.

     Maser


  5. The sounds having a frequency of 20 Hertz to 20,000 Hertz are known as

  6. A.

     Audible sounds

    B.

     Ultrasonics

    C.

     Infrasonics

    D.

     Megasonics


  7. In mirrors the back surface is coated with a thin layer of :

  8. A.

     Mercury

    B.

     Silver

    C.

     Red oxide

    D.

     Silver nitrate


  9. A light ray travelling from denser to rarer medium at an angle of incidence more than critical angle of concerned media pair suffers.

  10. A.

     Reflection

    B.

     Refraction

    C.

     Diffraction

    D.

     Total internal reflection


  11. The snow on the mountains does not melt all at once when it is heated by the sun because:

  12. A.

     It becomes very hard

    B.

     It reflects most of the heat from the sun

    C.

     It has a low specific heat capacity

    D.

     It has a high latent heat of fusion


  13. Cloudy nights are warmer compared to clear cloudless nights, because clouds mainly

  14. A.

     Absorb heat from the atmosphere send it towards earth

    B.

     Prevent cold waves from the sky descending on earth

    C.

     Reflect back the heat given by earth

    D.

     Produce heat and radiate it toward earth


  15. In which one of the following the phenomenon of total internal reflection of light is used ?

  16. A.

     Formation of mirage

    B.

     Working of binoculars

    C.

     Formation of rainbow

    D.

     Twinkling of stars


  17. Which type of mirror is used in the head lights of vehicles ?

  18. A.

     Plane mirror

    B.

     Concave mirror

    C.

     Convex mirror

    D.

     Parabolic mirror


  19. If objects appear enlarged and inverted in a rear view mirror, then which type of mirror is used?

  20. A.

     Concave

    B.

     Convex

    C.

     Cylindrical

    D.

     Plane