Question

Vikas is observing his photograph by keeping a rectangular glass slab of thickness $15\mathrm{cm}$on it. He wondered as he observed that his photograph was closer to him. By what distance his photograph is raised from the bottom of the glass slab?$(\mathrm{Take}{\mu }_{\mathrm{g}}=1.5)$

• A. $7.5\mathrm{cm}$
• B. $6\mathrm{cm}$
• C. $5\mathrm{cm}$
• D. $10\mathrm{cm}$

Answer 1

The correct option is C

$5\mathrm{cm}$

Step 1: Given the data and formula used

Given:

$\mathrm{Refractive}\mathrm{index}\left({\mathrm{\mu }}_{\mathrm{g}}\right)=1.5$

Real depth = $15cm$

Formula used: $\mu =\frac{\mathrm{Real}\mathrm{depth}}{\mathrm{Apparent}\mathrm{depth}}$

Step 2: Finding the apparent depth

On putting given value,

$1.5=\frac{15}{x}$

$\mathrm{x}=10\mathrm{cm}$

The distance raised by the photograph from the bottom of the glass slab is a shift $=15–10=5\mathrm{cm}.$
Hence, option C is correct.