Final answer:
The refractive index of the liquid is (a) 1.5.
Step-by-step explanation:
The refractive index of a liquid can be determined by using the lens formula:
1/f = (n_l - n)/R
Where,
- f is the focal length of the lens
- n_l is the refractive index of the lens in air
- n is the refractive index of the liquid
- R is the radius of curvature of the lens
Given that the power of the lens is 3 diopters when the refractive index of the lens is 1.25, and the power becomes 2 diopters when placed in a liquid, we can use the lens formula to find the refractive index of the liquid:
1/3 = (1.25 - n)/R
1/2 = (1.25 - n)/R
Solving these equations, we find that the refractive index of the liquid is 1.5.