{image} {image} {image} {image} {image}

1. 1. 2. 3. 4. 5. An electron has a velocity of {image} in the positive x direction at a point where the magnetic field has the components {image} {image} and {image} What is the magnitude of the acceleration of the electron at this point? • {image} • {image} • {image} • {image} • {image}

2. A particle {image} moves in a uniform magnetic field with a velocity having a magnitude of 3.0 km/s and a direction that is {image} away from that of the magnetic field. The particle is observed to have an acceleration with a magnitude of {image} What is the magnitude of the magnetic field? • 1.5 mT • 6.6 mT • 5.9 mT • 1.3 mT • 4.1 mT

3. A 6.0-C charge moves with a velocity of (2.0i + 4.0j + 6.0k) m/s and experiences a magnetic force of (4.0i - 20j + 12k) N. The x component of the magnetic field is equal to zero. Determine the y component of the magnetic field. • + 1.0 T • - 1.0 T • + 5.0 T • - 5.0 T • - 6.0 T

4. 1. 2. 3. 4. 5. A particle (mass = 1.0 mg, charge = {image} ) moves in the positive direction along the x axis with a velocity of 3.0 km/s. It enters a magnetic field of (2.0i + 2.0j + 3.0k) mT. What is the acceleration of the particle? • {image} • {image} • {image} • {image} • {image}

5. 1. 2. 3. 4. 5. A positively charged particle has a velocity in the positive z direction at point P. The magnetic force on the particle at this point is in the positive y direction. Which one of the following statements about the magnetic field at point P can be determined from this data? • {image} is positive. • {image} is negative. • {image} is positive. • {image} is negative. • {image} is positive.

6. A charged particle (mass = M, charge = Q > 0) moves in a region of space where the magnetic field has a constant magnitude of B and a upward direction. What is the magnetic force on the particle at an instant when it is moving horizontally toward the west with speed V? • QVB toward the north • QVB toward the east • Zero • QVB downward • QVB toward the south

7. A 2.0-m wire carries a current of 35 A directed along the positive x axis in a region where the magnetic field is uniform and given by B = (30i - 70j) mT. What is the resulting magnetic force on the wire? • (- 4.9 k) N • (+ 4.9 k) N • (- 9.8 k) N • (+ 9.8 k) N • (+ 0.80 k) N

8. A segment of wire carries a current of 26 A along the x axis from x = - 1.0 m to x = 0 and then along the y axis from y = 0 to y = 2.0 m. In this region of space, the magnetic field is equal to 30 mT in the positive z direction. What is the magnitude of the force on this segment of wire? • 1.7 N • 8.3 N • 2.7 N • 6.2 N • 9.3 N

9. A straight wire of length 80 cm carries a current of 50 A and makes an angle of {image} with a uniform magnetic field. If the force on the wire is 1.0 N what is the magnitude of B? • 25 mT • 65 mT • 57 mT • 33 mT • 62 mT

10. 1. 2. 3. 4. 5. A straight wire of length {image} carries a current {image} in the positive z direction in a region where the magnetic field is uniform and specified by {image} {image} and {image} where {image} is a constant. What is the magnitude of the magnetic force on the wire? • {image} • {image} • {image} • {image} • {image}

11. 1. 2. 3. 4. 5. A current of 3.0 A is maintained in a single circular loop having a circumference of 90 cm. An external magnetic field of 2.0 T is directed so that the angle between the field and the plane of the loop is {image} Determine the magnitude of the torque exerted on the loop by the magnetic forces acting upon it. • {image} • {image} • {image} • {image} • {image}

12. What current must be maintained in a square loop (70 cm on a side) to create a torque of {image} about an axis through its center and parallel to one of its sides when a magnetic field of magnitude 70 mT is directed at {image} to the plane of the loop? • 34 A • 49 A • 71 A • 72 A • 87 A

13. A wire (mass = 80 g, length = 70 cm) is suspended horizontally by two vertical wires which conduct a current {image} as shown in the figure. The magnetic field in the region is into the paper and has a magnitude of 80 mT. What is the tension in either wire? {applet} • 0.53 N • 0.76 N • 0.75 N • 0.32 N • 0.50 N

14. 1. 2. 3. 4. 5. A square loop (L = 0.30 m) consists of 60 closely wrapped turns, each carrying a current of 0.50 A. The loop is oriented as shown in a uniform magnetic field of 0.40 T directed in the positive y direction. What is the magnitude of the torque on the loop? {applet} • {image} • {image} • {image} • {image} • {image}

15. A circular coil (radius = 0.30 m) has 190 turns and is in a uniform magnetic field. When the orientation of the coil is varied through all possible positions, the maximum torque on the coil by magnetic forces is {image} when the current in the coil is 5.0 mA. What is the magnitude of the magnetic field? • 0.60 T • 0.71 T • 1.8 T • 1.9 T • 2.1 T

16. A deuteron is accelerated from rest through a 90-kV potential difference and then moves perpendicularly to a uniform magnetic field with B = 1.7 T. What is the radius of the resulting circular path? (deuteron: {image} {image} • 36 mm • 26 mm • 57 mm • 28 mm • 7.7 mm

17. A 900-eV electron and a 400-eV electron trapped in a uniform magnetic field move in circular paths in a plane perpendicular to the magnetic field. What is the ratio of the radii of their orbits? • 1.5 • 2.2 • 2.4 • 4.2 • 2.0

18. A proton moves around a circular path (radius = 1.0 mm) in a uniform 0.25-T magnetic field. What total distance does this proton travel during a 1.5-s time interval? {image} {image} • 36 km • 77 km • 91 km • 71 km • 3.2 km

19. A charged particle moves in a region of uniform magnetic field along a helical path (radius = 4.0 cm, pitch = 19 cm, period = 5.0 ms). What is the speed of this particle as it moves along this path? • 63 m/s • 69 m/s • 29 m/s • 20 m/s • 60 m/s

20. 1. 2. 3. 4. 5. Two single charged ions moving perpendicularly to a uniform magnetic field (B = 0.5 T) with speeds of 5,000 km/s follow circular paths that differ in diameter by 6.0 cm. What is the difference in the mass of these two ions? • {image} • {image} • {image} • {image} • {image}

21. What is the radius of curvature of the path of a 1.0-keV proton in a perpendicular magnetic field of magnitude 0.90 T? • 5.1 mm • 3.9 mm • 1.9 cm • 1.5 cm • 1.6 cm

22. An electron moves in a region where the magnetic field is uniform, has a magnitude of {image} and points in the positive x direction. At t = 0 the electron has a velocity that has an x component of 10 km/s, a y component of 30 km/s, and a z component of zero. What is the radius of the resulting helical path? • 2.4 mm • 5.8 mm • 5.4 mm • 5.6 mm • 11 mm

23. A proton with a kinetic energy of 0.30 keV follows a circular path in a region where the magnetic field is uniform and has a magnitude of 50 mT. What is the radius of this path? • 5.0 cm • 4.1 cm • 7.2 cm • 6.6 cm • 3.5 cm

24. A proton is accelerated from rest through a potential difference of 6.5 kV and then moves perpendicularly through a uniform 0.40-T magnetic field. What is the radius of the resulting path? • 29 mm • 20 mm • 82 mm • 47 mm • 2.2 mm

25. What is the kinetic energy of an electron that passes undeflected through perpendicular electric and magnetic fields if E = 4.0 kV/m and B = 8.0 mT? • 0.71 eV • 0.81 eV • 0.92 eV • 0.38 eV • 1.7 eV

26. A velocity selector uses a fixed electric field of magnitude E and the magnetic field is varied to select particles of various energies. If a magnetic field of magnitude B is used to select a particle of a certain energy and mass, what magnitude of magnetic field is needed to select a particle of equal mass but three times the energy? • 0.58 B • 0.33 B • 3.0 B • 1.7 B • 2.4 B

27. One reason why we know that magnetic fields are not the same as electric fields is because the force exerted on a charge {image} _____ . • is in opposite directions in electric and magnetic fields • is in the same direction in electric and magnetic fields • is parallel to a magnetic field and perpendicular to an electric field • is parallel to an electric field and perpendicular to a magnetic field • is zero in both if the charge is not moving

28. A coaxial cable has an inner cylindrical conductor surrounded by cylindrical insulation and an outer cylindrical conducting shell. The outer shell carries the same current but in the opposite direction from that in the inner conductor as shown. The coaxial cable sits in a uniform magnetic field directed downwards with respect to the cable. What is the effect of the field on the cable? {applet} • A net force to the left. • A net force to the right. • A net force upwards. • No net force but a slight shift of the inner conductor to the right and the outer conductor to the left. • No net force but a slight shift of the inner conductor to the left and the outer conductor to the right.

29. 1. 2. 3. 4. 5. A straight wire is bent into the shape shown. Determine the net magnetic force on the wire. {applet} • zero • {image} in the +z direction • {image} in the -z direction • {image} in the -z direction • {image} in the +z direction

30. The north-pole end of a bar magnet is held near a positively charged piece of plastic. The plastic is _____. • attracted • repelled • unaffected by the magnet

31. An electron moves in the plane of this paper toward the top of the page. A magnetic field is also in the plane of the page and directed toward the right. The direction of the magnetic force on the electron is _____. • toward the top of the page • toward the bottom of the page • toward the left edge of the page • toward the right edge of the page • upward out of the page • downward into the page

32. A wire carries current in the plane of this paper toward the top of the page. The wire experiences a magnetic force toward the right edge of the page. The direction of the magnetic field causing this force is _____. • in the plane of the page and toward the left edge • in the plane of the page and toward the bottom edge • upward out of the page • downward into the page

33. 1. 2. 3. 4. 5. Rank the magnitudes of the net forces acting on the rectangular loops shown in the figure below, from highest to lowest. All loops are identical and carry the same current. {image} • {image} • {image} • {image} • {image} • {image}

34. A charged particle is moving perpendicular to a magnetic field in a circle with a radius {image} The magnitude of the magnetic field is increased. Compared to the initial radius of the circular path, the radius of the new path is _____. • smaller • larger • equal in size