Arun
Last Activity: 7 Years ago
Dear Ayusha
RI = 1.6
P = 4D
From lens maker formula
P = (

-1) [1/R1 - 1/R2]
4 = (1.6-1) [1/R1 - 1/R2]
[1/R1 - 1/R2] = 4/0.6 = 20/3
RI of water = 1.33
Refractive index of glass wrt to water = 1.6/1.33
Power of lens in water = (1.6/1.33 -1)(20/3)
= 1.3533 D
Regards
Arun (askIITians forum expert)