When a ray of light enters from one medium to another medium, it deviates from its path, this phenomenon is called refraction.
Here, light is falling at an angle of incidence A in rarer medium and refracts at an angle B in denser medium. Again the ray is falling at an angle of incidence C in denser medium and then refract again in rarer medium.
At angle B, the light is refracted at an angle in one direction as it enters the glass. As it exits the glass at angle C, It is refracted at another angle in the opposite direction.
A short circuit is an electrical circuit that allows a current to travel along an unintended path. It has no or very low electrical impedances. The opposite of a short circuit