A proton moves around a circular path (radius = 2.0 mm) in a uniform 0.25-T magnetic field. What total distance does this proton travel during a 1.0-s time interval? (m = 1.67 1027 kg, q = 1.6 1019 C)
a. 82 km
b. 59 km
c. 71 km
d. 48 km
e. 7.5 km
[Ques. 2] A 500-eV electron and a 300-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?
a. 2.8
b. 1.7
c. 1.3
d. 4.0
e. 1.0
[Ques. 3] A deuteron is accelerated from rest through a 10-kV potential difference and then moves perpendicularly to a uniform magnetic field with B = 1.6 T. What is the radius of the resulting circular path? (deuteron: m = 3.3 1027 kg, q = 1.6 1019 C)
a. 19 mm
b. 13 mm
c. 20 mm
d. 10 mm
e. 9.0 mm
[Ques. 4] A circular coil (radius = 0.40 m) has 160 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 0.16 N / m when the current in the coil is 4.0 mA. What is the magnitude of the magnetic field?
a. 0.37 T
b. 1.6 T
c. 0.50 T
d. 1.2 T
e. 2.5 T
[Ques. 5] A rectangular coil (0.20 m 0.80 m) has 200 turns and is in a uniform magnetic field of 0.30 T. When the orientation of the coil is varied through all possible positions, the maximum torque on the coil by magnetic forces is 0.080 N / m. What is the current in the coil?
a. 5.0 mA
b. 1.7 A
c. 8.3 mA
d. 1.0 A
e. 42 mA
[Ques. 6] A straight 10-cm wire bent at its midpoint so as to form an angle of 90 carries a current of 10 A. It lies in the xy plane in a region where the magnetic field is in the positive z direction and has a constant magnitude of 3.0 mT. What is the magnitude of the magnetic force on this wire?
a. 3.2 mN
b. 2.1 mN
c. 5.3 mN
d. 4.2 mN
e. 6.0 mN
[Ques. 7] What current must be maintained in a square loop (50 cm on a side) to create a torque of 1.0 N / m about an axis through its center and parallel to one of its sides when a magnetic field of magnitude 70 mT is directed at 40 to the plane of the loop?
a. 66 A
b. 89 A
c. 61 A
d. 75 A
e. 37 A
[Ques. 8] What is the magnetic force on a 2.0-m length of (straight) wire carrying a current of 30 A in a region where a uniform magnetic field has a magnitude of 55 mT and is directed at an angle of 20 away from the wire?
a. 1.5 N
b. 1.3 N
c. 1.1 N
d. 1.7 N
e. 3.1 N
[Ques. 9] A straight wire of length L carries a current I in the positive z direction in a region where the magnetic field is uniform and specified by Bx = 3B, By = 2B, and Bz = B, where B is a constant. What is the magnitude of the magnetic force on the wire?
a. 3.2 ILB
b. 5.0 ILB
c. 4.2 ILB
d. 3.6 ILB
e. 1.0 ILB
[Ques. 10] What is the magnitude of the magnetic force on a charged particle (Q = 5.0 C) moving with a speed of 80 km/s in the positive x direction at a point where Bx = 5.0 T, By = 4.0 T, and Bz = 3.0 T?
a. 2.8 N
b. 1.6 N
c. 1.2 N
d. 2.0 N
e. 0.4 N
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