Final answer:
When the two-slit interference experiment is immersed in a swimming pool, the fringe pattern on the screen will be altered due to the change in the speed of light in water, resulting in a change in the spacing of the interference fringes.
Step-by-step explanation:
When the whole apparatus of a two-slit interference experiment is immersed in a swimming pool, the fringe pattern will be affected. The interference fringes arise due to the wave nature of light, and when the apparatus is immersed in water, the speed of light changes. This change in speed will lead to a change in the fringe spacing on the screen.
The change in the speed of light in water compared to air causes a change in the wavelength of the light. This change in wavelength will lead to a change in the spacing of the interference fringes on the screen. The fringes will become closer together or further apart depending on the change in wavelength.
Therefore, when the whole apparatus is immersed in the swimming pool, the fringe pattern on the screen will be altered due to the change in the speed of light in water, resulting in a change in the spacing of the interference fringes.