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The eye can be regarded as a single refracting surface. The radius of curvature of this surfac is equal to that of cornea (7.8 mm). This surface separates two media of refractive indices 1 an 1.34. Calculate the distance from the refracting surface at which a parallel beam of light wil come to focus. |
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Answer» 4.0 cm `n_2=1.34` `R_1=7.8 mm=0.78` `R_2=INFTY` For PARALLEL beam, `u~~infty` v=f (IMAGE is obtained at focus) `-1/u+1/v=(n_2-n_1)/(n_1)((1)/(R_1)-(1)/(R_2))` `THEREFORE (-1)/(infty)+1/f=(1.34-1)/(1.34)((1)/(0.78)-(1)/(infty))` `therefore1/f=(0.34)/(1.34)((1)/(0.78))` `therefore f=3.07=3.1` cm |
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