Part C: Finally, substitute the numerical values for all the known variables in the equation. Use your keyboard and the keypad to enter your answer. Then click Done.

Have You tried to search it i could not even answer that if i tried

convex lenses are thicker at the middle. rays of light that pass through the lens are brought closer together (they converge). a convex lens is a converging lens. when parallel rays of light pass through a convex lens the refracted rays converge at one point called the principal focus.

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 .