MCQ
When a telescope is adjusted for parallel light, the distance of the objective from the eye piece is found to be $80 \,cm$. The magnifying power of the telescope is $19.$ The focal lengths of the lenses are
  • A
    $61\,cm, 19 \,cm$
  • B
    $40 \,cm, 40\, cm$
  • $76 \,cm, 4 \,cm$
  • D
    $50 \,cm, 30\, cm$

Answer

Correct option: C.
$76 \,cm, 4 \,cm$
c
(c) ${f_o} + {f_e} = 80$ and $\frac{{{f_o}}}{{{f_e}}} = 19 ==>  f_o  = 76$ and $f_e$

$= 4 \,cm.$

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