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Ray Optics and Optical Instruments — Physics STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 SciencePhysicsRay Optics and Optical Instruments2 Marks
Question
  1. State the condition under which a large magnification can be achieved in an astronomical telescope.
  2. Give two reasons to explain why a reflecting telescope is preferred over a refracting telescope.
✓

Answer

  1. $m=-\frac{f_0}{f_e}$

By increasing 𝑓0 / decreasing 𝑓𝑒

  1.  
  1. No chromatic aberration.
  2. No spherical aberration.
  3. Mechanical advantage – low weight, easier to support.
  4. Mirrors are easy to prepare.
  5. More economical.

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