Conducting bar of length?

A conducting bar of length L = 55cm slides frictionlessly along a conducting rail that lies in a plane perpendicular to a magnetic field, as shown in the diagram. The bar is made to slide in the –x direction at a constant velocity of v = 3.2m/s. The magnetic field is not uniform, and it grows stronger as a function... show more A conducting bar of length L = 55cm slides frictionlessly along a conducting rail that lies in a plane perpendicular to a magnetic field, as shown in the diagram. The bar is made to slide in the –x direction at a constant velocity of v = 3.2m/s. The magnetic field is not uniform, and it grows stronger as a function of x according to:

B(x) = alpha x^2, alpha = 0.85 Tesla/m^2 (refer to image)

At the moment depicted in the diagram, the bar is at position x = 80cm.

a. Find the voltage drop across the lightbulb when the bar is at the position shown in the diagram. Include in your answer the side (right or left) of the lightbulb that is at higher voltage. Assume that the bar and rails have no resistance.

b. At the moment when the bar is at the position shown in the diagram, the force exerted on it to keep it moving at a constant speed is 15N. Find the resistance of the lightbulb.
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