Exam 29: Magnetic Fields

A current of 4.0 A is maintained in a single circular loop having a circumference of 80 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 20°.Determine the magnitude of the torque exerted on the loop by the magnetic forces acting upon it.

The figure shows the orientation of a rectangular loop consisting of 80 closely wrapped turns each carrying a current I.The magnetic field in the region is ( )mT)The loop can turn about the y axis.If θ = 30°,a = 0.40 m,b = 0.30 m,and I = 8.0 A,what is the magnitude of the torque exerted on the loop?

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

Three particles of equal charge,X,Y,and Z,enter a uniform magnetic field B.X has velocity of magnitude v parallel to the field.Y has velocity of magnitude v perpendicular to the field.Z has equal velocity components v parallel and perpendicular to the field.Rank the radii of their orbits from least to greatest.

An unusual lightning strike has a vertical portion with a current of −400 A downwards.The Earth's magnetic field at that location is parallel to the ground and has a magnitude of 30 μT.In N,the force exerted by the Earth's magnetic field on the 25 m-long current is

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 up out of the page,the direction of the magnetic field at P is closest to the direction of

An electron has a velocity of 6.0 × 10⁶ m/s in the positive x direction at a point where the magnetic field has the components B_x = 3.0 T,B_y = 1.5 T,and B_z = 2.0 T.What is the magnitude of the acceleration of the electron at this point?

A particle (q = −4.0 μC,m = 5.0 mg)moves in a uniform magnetic field with a velocity having a magnitude of 2.0 km/s and a direction that is 50° away from that of the magnetic field.The particle is observed to have an acceleration with a magnitude of 5.8 m/s².What is the magnitude of the magnetic field?

What is the magnitude of the magnetic force on a charged particle (Q = 5.0 μC)moving with a speed of 80 km/s in the positive x direction at a point where B_x = 5.0 T,B_y = −4.0 T,and B_z = 3.0 T?

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 × 10−²⁷ kg,q = 1.6 × 10−¹⁹ C)

A straight wire of length 70 cm carries a current of 50 A and makes an angle of 60° with a uniform magnetic field.If the force on the wire is 1.0 N what is the magnitude of B?

What is the kinetic energy of an electron that passes undeviated through perpendicular electric and magnetic fields if E = 4.0 kV/m and B = 8.0 mT?

A magnetic field is directed out of the page.Two charged particles enter from the top and take the paths shown in the figure.Which statement is correct?

A straight wire is bent into the shape shown.Determine the net magnetic force on the wire when the current I travels in the direction shown in the magnetic field )

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

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?

The point P lies along the perpendicular bisector of the line connecting two long straight wires S and T that are 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 up out of the page,the direction of the magnetic field at P is closest to the direction of

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 twice the energy?

A thin ribbon of a silver alloy 2.00-cm wide and 0.015 0-mm thick carries a current of 6.98 A perpendicular to a magnetic field.The Hall voltage is found to be 1.24 × 10−⁴ V when the magnetic field is 2.50 T.Calculate n,the number of charge carriers per cubic meter.

A uniform magnetic field of 0.50 T is directed along the positive x axis.A proton moving with a speed of 60 km/s enters this field.The helical path followed by the proton shown has a pitch of 5.0 mm.Determine the angle between the magnetic field and the velocity of the proton.