Magnetic field lines form in concentric circles around a cylindrical current-carrying conductor, such as a length of wire. The direction of such a magnetic field can be determined by using the "right hand grip rule" (see figure at right). The strength of the magnetic field decreases with distance from the wire. (For an infinite length wire the strength is inversely proportional to the distance.) Bending a current-carrying wire into a loop concentrates the magnetic field inside the loop while weakening it outside. Bending a wire into multiple closely spaced loops to form a coil or "solenoid" enhances this effect. A device so
What Is a Nation? What Is a Nation? "What is a Nation?" ("Qu'est-ce qu'une nation?") is an 1882 lecture by French historian Ernest Renan (1823–1892), known for the statements that a nation is "a daily referendum", and that nations are based as much on what the people jointly forget, as what they remember. It is frequently quoted or anthologized in works of history or political science pertaining to nationalism and national identity. Renan wrote "What is a Nation" in order to symbolize the nationalism which was born in France as a result of the French Revolution of 1789. Renan begins his essay by noting