Final answer:
Lightning rods are taller than buildings to provide a high point for lightning to strike, offering a direct and safe path to ground, and preventing damage by dissipating excess charge induced by electrical storms.
Step-by-step explanation:
Lightning rods are normally taller than the buildings they protect to provide a higher point for lightning to strike, which is option b. The primary purpose of a lightning rod is to protect the structure from damage by offering the easiest path to ground for electrical discharges. The sharp points on the rod collect excess charge from a building induced by the electrical storms, which can lead to a lightning strike. Since conductors with sharp corners or points will collect more charge at those points, the electrical field becomes very strong at the tip and can exert a force capable of moving charge. This allows any collected charge to dissipate back into the air, minimizing the risk of a lightning bolt directly striking the building and causing damage. Hence, having a taller lightning rod, usually mounted on the highest point of a building, ensures that it is the most likely strike point, and because it is well-grounded, it safely directs the energy of the lightning into the ground.