Assume the Earth\'s magnetic field is 52.8 Assume the Earth\'s magnetic field is
ID: 2279032 • Letter: A
Question
Assume the Earth's magnetic field is 52.8
Assume the Earth's magnetic field is 52.8 mu T northward at 60.0 degree below the horizontal in a particular city. A tube in a neon sign stretches between two diagonally opposite corners of a shop window-which lies in a north-south vertical plane-and carries current 32.7 mA. The current enters the tube at the bottom south corner of the shop's window. It exits at the opposite corner, which is 1.33 m farther north and 0.850 m higher up. Between these two points, the glowing tube spells out DONUTS. Determine the total vector magnetic force on the tube. Hint: Two very important general statements are as follows. First, the force on the curved portion is the same in magnitude as the force on a straight wire between the same two points. In general, the magnetic force on a curved current-carrying wire in a uniform magnetic field is equal to that on a straight wire connecting the endpoints and carrying the same current. Furthermore, F1 rightarrow + F2 rightarrow = 0 is also a general result: the net magnetic force acting on any closed current loop in a uniform magnetic field is zero. (Take east to be the +x-axis, up to be the +y-axis, and south to be the +z-axis.)Explanation / Answer
distnace d = sqrt ( 1.33^2 + 0.85^2) = 1.578 m
force F = ilB sin theta
F =0.0327 * 1.578 * 52.8*10^-6 sin (90-60)
F = 1.36 uN