Chapter 28, Problem 030 GO In the figure, an electron with an initial kinetic energy of 3.90 keV enters region 1 at time t = 0. That region contains a uniform magnetic field directed into the page, with magnitude 0.0120 T. The electron goes through a half-circle and then exits region 1, headed toward region 2 across a gap of 30.0 cm. There is an electric potential difference AV = 2000 V across the gap, with a polarity such that the electron's speed increases uniformly as it traverses the gap. Region 2 contains a uniform magnetic field directed out of the page, with magnitude 0.0206 T. The electron goes through a half-circle and then leaves region 2. At what time t does it leave? Region 1 Region 2 OBĄ Chapter 28, Problem 047 GO A copper rod of mass m = 1.08 kg rests on two horizontal rails a distance L = 0.923 m apart and carries a current of i= 49.0 A from one rail to the other. A top view and a side view are shown in the figure. The coefficient of static friction between rod and rails is μ = 0.640. What are the (a) magnitude and (b) angle (relative to the vertical) of the smallest magnetic field that puts the rod on the verge of sliding? Rail Rod Rod Gal Rail Rail

Chapter 28, Problem 030 GO In the figure, an electron with an initial kinetic energy of 3.90 keV enters region 1 at time t = 0. That region contains a uniform magnetic field directed into the page, with magnitude 0.0120 T. The electron goes through a half-circle and then exits region 1, headed toward region 2 across a gap of 30.0 cm. There is an electric potential difference AV = 2000 V across the gap, with a polarity such that the electron's speed increases uniformly as it traverses the gap. Region 2 contains a uniform magnetic field directed out of the page, with magnitude 0.0206 T. The electron goes through a half-circle and then leaves region 2. At what time t does it leave? Region 1 Region 2 OBĄ Chapter 28, Problem 047 GO A copper rod of mass m = 1.08 kg rests on two horizontal rails a distance L = 0.923 m apart and carries a current of i= 49.0 A from one rail to the other. A top view and a side view are shown in the figure. The coefficient of static friction between rod and rails is μ = 0.640. What are the (a) magnitude and (b) angle (relative to the vertical) of the smallest magnetic field that puts the rod on the verge of sliding? Rail Rod Rod Gal Rail Rail