A spherical air lens of radii R1 = R2 = 10 cm is cut from a glass (μ = 1.5) cylinder as shown in figure. Its focal length is f1. If a liquid of refractive index 2 is filled in the space then the focal length of liquid lens becomes f2. Calculate f1 and f2. Choose the correct options from the following.
1
f1 = 15 cm. f2 = 30 cm
2
f1 = -15 cm, f2 = +30 cm
3
f1 = -15 cm. f2 = +15 cm
4
f1 = -30 cm, f2 = -15 cm