Question

A converging meniscus lens has an index of refraction of 1.55 and radii of curvature for its surfaces of 4.60 cm and 9.20 cm. The concave surface is placed upward and filled with carbon tetrachloride (CCl4), which has n = 1.46. What is the focal length of the CCl4-glass combination?

Answer 1

Answer: the focal length of the CCl4-glass combination is 102.31 cm

Explanation:

Given that;

Index of refraction n1 = 1.55

carbon tetrachloride (CCl4), which has n2 = 1.46

radii of curvature for its surfaces R1 = 4.6cm and R2 = 9.20 cm

the focal length of the CCl4-glass combination = ?

we can determine the focal length using the Formula;

1/f = ( n1 - n2) ( 1/R1 - 1/R)

so we substitute in our values

1/f = ( 1.55 - 1.46 ( 1/4.6 - 1/9.20)

1/f = 0.09 × 0.1086

1/f = 0.009774

f = 1 / 0.009774

f = 102.31 cm

Therefore the focal length of the CCl4-glass combination is 102.31 cm