A biconvex thick lens is constructed with glass (μ = 1.50). Each of the surfaces has a radius of 10 cm and the thickness at the middle is 5 cm. Locate the image of an object placed far away from the lens.

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Biconvex lens with each surface has a radius (


Thickness of lens (t) = 5 cm


Refractive index of lens ==1.50


Position of object =


At first refraction occurs at A


By using lens equation:



⇒


⇒


⇒


Now, the second refraction occurs at B


Object distance =u= (30-5) = 25 cm (a virtual object)


Radius


So, (by using lens equation)



So, the image is formed 9.1 cm further from the 2nd surface of the lens.


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