A new fountain was built in a school, and a spotlight was installed in the center of the pool bottom. When there is no water in the pool, a beam of light from the spotlight shines on the pool wall, fo

A new fountain was built in a school, and a spotlight was installed in the center of the pool bottom. When there is no water in the pool, a beam of light from the spotlight shines on the pool wall, forming a pool at point S. Basic knowledge analysis: (1) Light travels in a straight line in the same, uniform and transparent medium. When it enters another medium from one medium, the propagation direction of light changes and refraction occurs;

(2) When the water surface rises to position A, when the light enters the air obliquely from the water, the incident light, the refracted light and the normal line are in the same plane, and the refraction angle is greater than the incident angle, thus determining the direction of the refracted light;

(3) When the water level rises to position B, the light first reflects on the side wall of the pool with a reflection angle equal to the incident angle, and then the reflected light is obliquely refracted from the water into the air with a refraction angle greater than the incident angle.

Solution: (1) When water is injected into the pool, it will be refracted when the water surface rises to position A. According to the law of refraction, point P is shown in the following figure:

(2) When the water surface rises to position B, the light first reflects on the pool wall and then refracts out of the water surface. According to the laws of reflection and refraction, the Q point is shown in the following figure:

By drawing, we can know that point P is below point S and point Q is above point S.

So choose a.

I hope it will help your study!