Final answer:
The focal length of a lens in water, with an index of refraction of 1.52 for the lens and 1.33 for water, originally having a 25.0 cm focal length in air, is calculated to be 21.875 cm.
Step-by-step explanation:
To calculate the focal length of a lens in water, we can adjust the lens maker's equation given the index of refraction of the lens (n_lens=1.52) and the index of refraction of water (n_water=1.33). The focal length in air is given as 25.0 cm. According to the lens maker's equation, the focal length of the lens in a different medium can be found using the ratio of the indices of refraction of the two media. The equation for switching media is:
f_water = f_air * (n_water / n_lens)
Plugging in the known values:
f_water = 25.0 cm * (1.33 / 1.52)
Performing the calculation provides us with the focal length of the lens in water:
f_water = 25.0 cm * 0.875
f_water = 21.875 cm
Thus, the focal length of the lens in water is 21.875 cm.