Question

Chapter 28. A metal, u-shaped bar is situated so that its two ends are each resting in a cup of mercury. The bar is in a uniform magnetic field which is orthogonal to the bar. When a current is applied through the mercury and bar, it experiences a force that will send it flying upward. (a) Draw a sketch and label all relevant vectors involved in this scenario. If the bar has mass of 0.050 kg, a length of 0.10m, and the magnetic field has a magnitude of 20 mT, what must be the minimum current (direction and magnitude) to lift the bar? (Shown in the film "Francis Bitter's Magnet Lab" on the AFANA site (Academic Film Archive of North America)) 5 rticular roginn there it a

Answer 1

BIL =mg

l L B= m g

l =~A, 0.05*9.81/(0.2*0.1)=2.45A