An electron microscope can reveal detail that a light microscope cannot because

  • A. it magnifies the specimen many more times
  • B. the wavelength of an electron beam is far shorter, giving much greater resolving power
  • C. it can be used on living specimens
  • D. it uses ultraviolet light instead of visible light

Explanation

Resolution is limited by wavelength, and the very short wavelength of an electron beam allows two points less than a nanometre apart to be seen as separate, against about 200 nanometres for a light microscope. Magnification without resolution simply enlarges a blur, which is the distinction the question is testing. The specimen must be dead and in a vacuum, so living material cannot be examined.

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