Exam 29: Magnetic Fields

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 × 10−²⁷ kg,q = 1.6 × 10−¹⁹ C)

A circular loop (radius = 0.50 m)carries a current of 3.0 A and has unit normal vector of ( )/3)What is the x component of the torque on this loop when it is placed in a uniform magnetic field of ( )T?

A square loop (L = 0.20 m)consists of 50 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?

The point P lies along the perpendicular bisector of the line connecting two long straight wires S and T perpendicular to the page.A set of directions A through H is shown next to the diagram.When the two equal currents in the wires are directed into the page,the direction of the magnetic field at P is closest to the direction of

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 particle (mass = 6.0 mg)moves with a speed of 4.0 km/s in a direction that makes an angle of 37° above the positive x axis in the xy plane.At the instant it enters a magnetic field of (5.0 )mT it experiences an acceleration of (8.0 )m/s².What is the charge of the particle?

A stream of electrons passes through a velocity filter where the crossed magnetic and electric fields are 0.020 T and 5.00 × 10⁴ V/m,respectively.Find the kinetic energy (in electron volts)of the electrons passing through the filter.[1 eV = 1.60 × 10−¹⁹ J]

A wire (mass = 50 g,length = 40 cm)is suspended horizontally by two vertical wires which conduct a current I = 8.0 A,as shown in the figure.The magnetic field in the region is into the paper and has a magnitude of 60 mT.What is the tension in either wire?

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 proton is accelerated from rest through a potential difference of 2.5 kV and then moves perpendicularly through a uniform 0.60-T magnetic field.What is the radius of the resulting path?

A charged particle moves in a region of uniform magnetic field along a helical path (radius = 4.0 cm,pitch = 20 cm,period = 2.0 ms).What is the speed of the particle as it moves along this path?

An electron moves in a region where the magnetic field is uniform,has a magnitude of 60 μT,and points in the positive x direction.At t = 0 the electron has a velocity that has an x component of 30 km/s,a y component of 40 km/s,and a z component of zero.What is the radius of the resulting helical path?

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 B_x = 3B,B_y = −2B,and B_z = B,where B is a constant.What is the magnitude of the magnetic force on the wire?

The reason the north pole of a bar magnet free to rotate points north is because

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?

An electron follows a circular path (radius = 15 cm)in a uniform magnetic field (magnitude = 3.0 G).What is the period of this motion?

The diagram below shows the position of a long straight wire perpendicular to the page and a set of directions labeled A through H.When the current in the wire is directed up out of the page,the direction of the magnetic field at point P is

An explorer walks into a lab in a science building.She has a compass in her hand and finds that the south pole of her compass points toward the room's East wall when she is nearer that wall and toward the west wall when she is nearer that wall.You could explain this if magnetized metal had been installed in the East and West walls with North poles pointing into the room.If no magnetic material was installed in the North or South walls of the room,she would expect that

An electron moves in a region where the magnetic field is uniform,has a magnitude of 60 μT,and points in the positive x direction.At t = 0 the electron has a velocity that has an x component of 30 km/s,a y component of 40 km/s,and a z component of zero.What is the pitch of the resulting helical path?

A straight wire carries a current of 40 A in a uniform magnetic field (magnitude = 80 mT).If the force per unit length on this wire is 2.0 N/m,determine the angle between the wire and the magnetic field.