To practice problem-solving strategy 27.2 motion in magnetic fields. an electron inside of a television tube moves with a speed of 2.74×107 m/s . it encounters a region with a uniform magnetic field oriented perpendicular to its trajectory. the electron begins to move along a circular arc of radius 0.190 m . what is the magnitude of the magnetic field? part ccalculate the magnitude f of the force exerted on the electron by a magnetic field of magnitude 8.21×10−4 t oriented as described in the problem introduction. express your answer in newtons.