1. At a certain moment in time, two identical, positively chargedparticles are flying horizontally toward each other. Let thexx-axis be the axis along which the particles are moving, and letthe origin lie directly between both particles. Let the yy-axis beoriented pointing vertically up and the zz-axis point directly outfrom the origin.
   
   1) Which combination of options below are the best combination ofcorrections that you might make to your friend's diagram? [Enteryour answer as a string of the letter options you believe arecorrect. For instance, if you think options A, D, and E arecorrect, then enter \"ADE\"]
   
   A) The particles exert magnetic forces on each other.
   B) The magnetic fields of each particle reinforce each other atpositions equidistant from each of the particles.
   C) The total magnetic field at points vertically above the positivexx-axis point in the positive zz direction.
   D) The total magnetic field at points vertically below the negativexx-axis point in the negative zz direction.
   E) None of the above
2. A circular loop of wire has current flowing through it. You arelooking straight down at this loop from above. The flow of thecurrent through the loop relative to you can be either clockwise orcounter-clockwise around the loop. The options describe a series ofexperiments involving either a magnet or another current loopbrought down toward the original. The current in the original loopcan be changed between experiments. Choose the combination ofoptions below are physically consistent. [Enter your answer as astring of the letter options you believe are correct. For instance,if you think options A, D, and E are correct, then enter\"ADE\"]
   
   A) A magnet's south pole is repelled as it is brought down to theloop from above. Therefore, the current flows clockwise.
   B) A magnet's north pole is repelled as it is brought down to theloop from above. Therefore, the current flowscounter-clockwise.
   C) A counter-clockwise current loop above the original isattracted. Therefore, the current flows clockwise.
   D) A clockwise current loop above the original is repelled.Therefore, the current flows counter-clockwise.
   E) None of the above
3. Two positively charged particles are travelling through spacein each others' vicinity. Using the standard xx-yy-zz coordinategrid, particle 1 travels along the positive xx direction whileparticle 2 travels along the positive yy direction, headingdirectly for the first particle from below.
   
   Which combination of options below are the most accuratecombination of statements. [Enter your answer as a string of theletter options you believe are correct. For instance, if you thinkoptions A, D, and E are correct, then enter \"ADE\"]
   
   A) Particle 1's magnetic field at particle 2's location points inalong the zz-axis.
   B) Particle 2 feels a magnetic force pushing down the negative yydirection.
   C) Particle 2's magnetic field at the location of particle 1 iszero.
   D) Particle 1 feels no magnetic force due to particle 2's magneticfield.
   E) None of the above
4. An electric motor is a device that transfers electricallystored energy into kinetic energy. A very crude one would consistof a conducting wire shaped as a loop with a steady electriccurrent passing through it placed in a uniform magnetic field.Let's imagine that the magnetic field is directed along thepositive xx-axis, which we'll set up as going from left to right.The yy-axis points up and the zz-axis points out. Assume an absenceof any frictional effects.
   
   Which combination of options below are the most accuratecombination of statements? [Enter your answer as a string of theletter options you believe are correct. For instance, if you thinkoptions A, D, and E are correct, then enter \"ADE\"]
   
   A) If the current loop's dipole moment is initially aligned withthe field, there will be no resulting rotational motion.
   B) Maximum potential energy in this system occurs when the dipolemoment points in the −i^−i^ direction
   C) If the dipole moment initially points along the k^k^ direction,it's left end will feel a force pushing up along the j^j^direction.
   D) If the dipole moment initially points along the k^k^ direction,it's right end will feel a force pushing in along the −k^−k^direction.
   E) None of the above
5. An electron gun sends out a beam of electrons whose kineticenergies are all about 54 μμeV. (1 μeV=1.6×10−25 J1 μeV=1.6×10−25J.) You need to set up a magnetic field perpendicular to the beamthat causes it to turn through a 90∘∘ circular arc of length 2 mm.How strong must the magnetic field be?
6. You take a wire and wind it into a circular loop (leaving thetwo ends free so that they can be connected to a power supply). Youtake a longer wire and wind it around making 6 turns of the sameradius as your first single loop. If you run the same amount ofcurrent through both wires, compare the magnetic dipole momentmagnitudes of the two setups. What is the ratio of the multi-loopcurrent's dipole moment magnitude to that of the single loopcurrent?
7. Two particles, both carrying charge 6 C are traveling parallelto each other with velocities of v⃗ =12000i^v→=12000i^ in m/s. Theyare positioned at the points (0,2,0)(0,2,0) and (0,−2,0)(0,−2,0).What is the magnitude and direction of the magnetic field at(0,2,0)(0,2,0) due to the particle located at (0,−2,0)(0,−2,0)?[Enter the magnitude in answer box 1 and the direction as one ofeither \"in\", \"out\", \"up\", \"down\", \"left\", or \"right\" in answer box2. Assume that the xx-axis corresponds to left/right, the yy-axiscorresponds to up/down, and the zz-axis corresponds toin/out.]
8. What is the force exerted by the magnetic field you calculatedabove on the particle at that location? Compare this to thedirection of the electric force on the particle. [Enter themagnitude of the force in the first answer box and its direction inthe second. Enter the direction of the electric force on theparticle in the third box. For the directions enter either \"in\",\"out\", \"up\", \"down\", \"left\", or \"right\"]
9. How fast would the particles have to travel in order for thereto be a balance between the magnetic and electric forces they exerton each other?
10. Geordi La Forge was born blind, but has a VISOR that allows himto perceive a broad range of the electromagnetic spectrum. Let'ssuppose that there's a setting that allows Geordi to distinguishelectric and magnetic fields from one another. The VISOR also giveshim readings on voltage differences between various points inspace. If Geordi were to walk by a uniform magnetic field that wasnot moving relative to the ground, what would he see?
    
    Choose the best combination of options below. [Enter your answer asa string of the letter options you believe are correct. Forinstance, if you think options A, D, and E are correct, then enter\"ADE\"]
    
    A) Identical magnetic field vectors at every point in space.
    B) There would only be magnetic field vectors since their are noelectric field sources.
    C) Non-zero voltage differences along displacements perpendicularto the magnetic field vectors.
    D) Non-zero voltage differences along displacements parallel to themagnetic field vectors.
    E) None of the above
11. A loop of copper (a conducting material) is carried across aregion of space with a non-zero uniform magnetic field so that thearea surrounded by the loop is perpendicular to the fielddirection. Imagine the situation is oriented so that the magneticfield is coming out of the screen toward you, and the loop is beingpulled toward the right.
    
    Which combination of options below is most accurate? [Enter youranswer as a string of the letter options you believe are correct.For instance, if you think options A, D, and E are correct, thenenter \"ADE\"]
    
    A) The magnetic flux through the loop is decreasing.
    B) The induced current flows clockwise.
    C) Nothing would be changed if the field were not uniform.
    D) Turning the loop around would induce a current.
    E) None of the above