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When the same monochromatic ray of light travels through glass slab and through water, the number of waves in glass slab of thickness 6 cm is same as in water column of height 7 cm. If refractive index of glass is `1.5`, then refractive index of water isA. `1.25`B. `1.5`C. `1.33`D. `1.75` |
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Answer» Correct Answer - C Number of waves in a medium (N) `=("Thickness")/("Wavelength in the medium")` `:. N_("glass")=N_("water")` `:. (4)/(lambda_g)=(5)/(lambda_w) :. (lambda_g)/(lambda_w)=(4)/(5)` but `lambda prop (1)/(R.I.) :. (n_w)/(n_g)=(lambda_g)/(lambda_w)` `:. n_W=n_g xx (lambda_g)/(lambda_w)=(5)/(3) xx(4)/(5)=(4)/(3)=1.33` |
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