16.Ang Speed.What is the angular speed of the electron?A – 5
Second Long ExamSecond Semester, AY 2015–2016Physics 72A.2.85×10-14rad/sB.3.51×1013rad/sC.1.14×10-9rad/sD.8.78×108rad/sE.17.Bilis.If the electron follows a circular orbit with radius5 cm, what is the speedvof theelectron?For the next two items, consider aprotonwith initial velocityv0ˆımoving in a region withuniform fieldsB=B0ˆkandE=E0ˆk.18.True that.Which of the following isTRUEabout the initial net force on the proton?I. It is purely due to the magnetic field.II. It has a component along the-y-direction.III. It has a component along the+z-direction.19.Trajectory.Which of the following is a possible trajectory of the proton?A – 6
Second Long ExamSecond Semester, AY 2015–2016Physics 7220.FL tower.Two straight, parallel wires0.20 mapart carry currents in opposite directions asshown. What is the force per unit length exerted on each wire?A.28×10-6N/m, attractiveB.28×10-6N/m, repulsiveC.28π×10-6N/m, attractiveD.28π×10-6N/m, repulsiveE.21.Coilbie Coillat.A tightly-wound circular coil with radius4 mand 25 turns carries a currentof2 A. What is the magnetic field along the coil’s axis at a distance of3 mfrom its center?For the next two items, consider a long cylindrical conductor with radiuscand current densityJuniformly distributed over its cross-sectional area. Letrbe an arbitrary distance from theconductor’s axis.22.Si Jc o si Jr?What is the magnetic field magnitude inside the conductor (r < c)?23.B vs. r.Which of the following gives the correct plot of the magnetic field magnitudeBas a function ofr?A – 7
Second Long ExamSecond Semester, AY 2015–2016Physics 7224.Moving Charge.Consider a point charge+qlocated at the origin and moving at a constantvelocityv=πm/sˆk. At this instant, what is the magnetic field vector at(0,0.5 m,0)?A.+μoq16ˆıB.+μoqˆıC.-μoqˆıD. zeroE.A – 8
Second Long ExamSecond Semester, AY 2015–2016Physics 72