Study

Lenses and its application

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  • What are four main photometric quantities?
    luminous flux, luminous intensity, luminance and illuminance
  • In compound microscope, a --------------- mounted beneath the slides can be adjusted to give reflected light to object.
    concave mirror
  • In astronomical telescope, a concave mirror used as the -------- instead of a convex lens.
    objective
  • luminous flux is measured in --------
    lumen (lm)
  • In refracting astronomical telescope, to obtain sharp image of the distant objects the objective should have a ----- diameter.
    large
  • In astronomical telescope, the final image formed by the eyepiece is -------, ----- than the first image.
    virtual / larger
  • Formula of magnifying power of compound microscope is
    MP = vo / uo ( 1 + D/ f e )
  • In normal adjustment, the final image is at ----
    infinity
  • What are the units of luminous intensity, solid angle, luminance and illuminance?
    candela or lumen per steradian , steradian , candela per metre squared , lux
  • In compound microscope, the objective lens produces an image which is -----, --- and ------ the size of the object.
    real, inverted , larger than
  • Due to an eyeball is too short or due to the eye - lens cannot be sufficiently convex can be caused
    farsightedness or hyperopia
  • What are two main types of electron microscope?
    scanning electron microscope(SEM) and transmission electron microscope (TEM)
  • ------- are attached to the eye lens.
    The ciliary muscles
  • Binoculars use total reflecting prisms. Why?
    Because of the successive total internal reflections prisms, the length of the telescope is greatly reduced.
  • The light sensitive area of the cells, at the back of the eye is ----
    the retina
  • In normal adjustment, the separation of lenses ; L =
    v o + f e
  • Which lenses use in electron microscopes?
    electrostatic or electromagnetic
  • The pupil automatically contracts in ------- light
    bright
  • The optical instrument can be used for viewing distant objects is called a -----
    telescope
  • A magnifying glass that has a bi-convex lens with a short focal length is a
    simple microscope
  • Myopia can be corrected by using spectacles with ------- lenses.
    concave
  • the front portion of the eye is covered by a tough, transparent membrane
    cornea
  • For normal person, the least distance of distinct vision is
    25 cm
  • What are widely used as terrestrial telescopes?
    binoculars
  • Electron microscopes use electrons which have shorter wavelength that allow ---- magnification.
    greater
  • Sign convention , the heights below the principal axis are _____
    negative or minus
  • two transparent liquids contains human eye are
    aqueous humour and vitreous humour
  • Lenses marker's formula
    1/f = (n - 1) [ 1/ R1 - 1/R2 ]
  • A compound microscope has at least two convex lenses; an ---- lens and an ----- lens.
    objective / eyepiece
  • Formula of the inverse square law of illuminance is
    Ev = Iv cos theta / r2