# Calculate the Focal Length of a Convex Lens Whose Radii of Curvature of Two Surfaces is 10 Cm and 15 Cm Respectively and Its Refractive Index is 1.5. - Physics (Theory)

Numerical

Calculate the focal length of a convex lens whose radii of curvature of two surfaces is 10 cm and 15 cm respectively and its refractive index is 1.5.

#### Solution

Given :

f = ?  R_1 =10  "cm"    R_2 = 15  "cm"  mu = 1.5

1/f = (mu - 1)(1/R_1 - 1/R_2)

1/f = (1.5 - 1)(1/10 - 1/15)

1/f = (0.5)(0.1 - 0.066)

= (0.5)(0.034)

1/f = 0.017

therefore f = 58.82  "cm"`

Concept: Lenses
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