These effects are derived from two fundamental observations of physics: a steady current creates a steady magnetic field described by Oersted's law, and a time-varying magnetic field induces an electromotive force in nearby conductors, which is described by Faraday's law of induction.
Butter & salt. Preheat the oven to 400 degrees. Husk the corn, wrap each ear in foil, adding 2 teaspoons of butter to each packet. Bake for about 25 minutes or roast the foil-wrapped corn over hot coals turning once during the cooking. Serve with more butter and salt.
Rub the ears with a little butter, and salt and pepper them judiciously. Wrap the ears in aluminum foil. Place on a rack in the oven and cook for 20 minutes. If they're big, heavy ears  what people used to call roasting corn  it may take as long as 30 minutes.