Final answer:
The correct answer is c. It would increase. The magnitude of the power of a lens will increase when it is placed in water
Step-by-step explanation:
When a lens is placed in water (with a refractive index of 1.33), the magnitude of its power will change. This is because the focal length of the lens depends on the refractive index of the medium surrounding it. As the refractive index of water is different from that of air, the focal length of the lens will change when submerged in water.
A converging lens, also known as a convex lens, has a positive power. When placed in water, the power of a converging lens will decrease because the refractive index of water is greater than that of air. Conversely, a diverging lens, also known as a concave lens, has a negative power. When placed in water, the power of a diverging lens will increase because the refractive index of water is greater than that of air.
Therefore, the correct answer is c. It would increase.