MCQ
One face of a rectangular glass plate $6 \,cm$ thick is silvered. An object held $8\, cm$ in front of the first face, forms an image $12\, cm$ behind the silvered face. The refractive index of the glass is
  • A
    $0.4$
  • B
    $0.8$
  • $1.2$
  • D
    $1.6$

Answer

Correct option: C.
$1.2$
c
(c) Let $ x$ be the apparent position of the silvered surface.

According to property of plane mirror

$x + 8 = 12 + 6 -x  \Rightarrow x = 5 cm$

Also $\mu = \frac{t}{x}$$ \Rightarrow $$\mu = \frac{6}{5} = 1.2$

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