Aray of light is traveling in a glass cube that is totally immersed in water. you find that if the ray is incident on the glass–water interface at an angle to the normal larger than no light is refracted into the water. what is the refractive index of the glass?

answer: the answer is a

r=rho l/a where a is the area, l is the length and rho is resistivity so the greater the area the lesser the resistance thats why the earth pin is thicker bcos current follow the shortest path, so less resistive .

positive reinforcement? ?

the entire statement is true and correct.  

there's no diagram, nothing is illustrated, and no question is asked.