Consider the system pictured in the figure below. A = 16-cm length of conductor
ID: 1643217 • Letter: C
Question
Consider the system pictured in the figure below. A = 16-cm length of conductor of mass 27 g, free to move vertically, is placed between two thin, vertical conductors, and a uniform magnetic field acts perpendicular to the page. When a 5.0-A current is directed as shown in the figure, the horizontal wire moves upward at constant velocity in the presence of gravity.
(a) What forces act on the horizontal wire, and under what condition is the wire able to move upward at constant velocity?
This answer has not been graded yet.
(b) Find the magnitude and direction of the minimum magnetic field required to move the wire at constant speed.
(c) What happens if the magnetic field exceeds this minimum value? (The wire slides without friction on the two vertical conductors.)
Explanation / Answer
a) Forces acting on the horizontal wire include : magnetic and gravitational field. When the magnetic force is upward and balances the downward gravitational force, the net force on the wire is zero, and the wire can move upward at constant velocity.
b) for forces acting along the y-direction ,
Forces along y = magnetic force - m*g =0
And magnetic force = i*l*B
So , i*l*B =m*g
B = (m*g)/(i*l) = (0.027*10)/(5*0.16) = 0.3375 T
c) if the field exceeds the above magnitude , the upward magnetic force will exceed the downward force of gravity and the wire will accelerate upward.