• When a beam of light is used to determine the position of an object, the maximum accuracy is achieved if the light is



  • @pranav-mahajan

    The maximum accuracy in finding the position of an object using a light beam is achieved, when the light
    beam used is of shorter wavelength. If the wavelength is longer, the spread in the be will be more.

  • To see an object it is necessary for light to reflect off that object and enter into our eye. This means that light is the carrier of information, light when reflects off a surface of an object carries with it the information of how the surface looks. Hence, it is necessary for light to reflect and to reflect without disturbing or without bringing any change to the object from which it is reflecting.

    I am assuming that by particle you mean the subatomic particles whose size are comparable to the wavelength of light or may even be smaller than the wavelength of light.

    For light to reflect the most necessary condition is that the dimensions of the particle from which it is reflecting should be greater than the wavelength of light used.

    Just imagine light approaching a particle smaller that its wavelength. It would be just like a car approaching a small toy placed on the road.

    What would happen here ?

    The car will just pass over the toy as if the toy were not even there. Similarly in the case of light, the light will just pass completely ignoring the particle. If somehow light hits the particle it'll just deflect the particle from it's path without itself getting reflected.

    Hence to see/ to know the position of a particle it is necessary to use light of shorter wavelength. The more shorter the wavelength of light used the more accurate is the position we measure.

    PS: This is the reason for Heisenberg's uncertainity principle. The subatomic particles are so small and so light that none of the wavelength of electromagnetic radiation gives us the accurate position. If the accuracy in position increases, i.e the wavelength of light used is small which means the energy of light is more, the particle gets deflected when light hits it because of large energy of light. And hence there is no way to determine it's new position.

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