Exam 21: Magnetic Forces and Magnetic Fields

A particle with a mass of 6.64 × 10^-27 kg and a charge of +3.20 × 10^-19 C is accelerated from rest through a potential difference of 2.45 × 10⁶ V. The particle then enters a uniform 1.60-T magnetic field. If the particle's velocity is perpendicular to the magnetic field at all times, what is the magnitude of the magnetic force exerted on the particle?

A wire is bent into the shape of a circle of radius r = 0.10 m and carries a 20.0-A current in the direction shown. -Determine the magnetic moment of the loop.

A long, straight, vertical segment of wire traverses a magnetic field of magnitude 2.0 T in the direction shown in the diagram. The length of the wire that lies in the magnetic field is 0.060 m. When the switch is closed, a current of 4.0 A flows through the wire from point P to point Q. -What is the magnitude of the magnetic force acting on the wire?

A single circular loop of wire with radius 0.025 m carries a current of 6.0 A. It is placed at the center of a solenoid that has length 0.60 m, radius 0.075 m, and 1200 turns. -Determine the magnitude of the total magnetic field at the center of the loop (due both to the loop and the solenoid) if the current in the loop is reversed in direction from that needed to make the total field equal to zero tesla.

A solenoid of length 0.250 m and radius 0.0250 m is comprised of 440 turns of wire. Determine the magnitude of the magnetic field at the center of the solenoid when it carries a current of 12.0 A.

A proton is traveling south as it enters a region that contains a magnetic field. The proton is deflected downward toward the earth. What is the direction of the magnetic field?

A long, coaxial cable, shown in cross-section in the drawing, is made using two conductors that share a common central axis, labeled C. The conductors are separated by an electrically insulating material that is also used as the outer cover of the cable. The current in the inner conductor is 2.0 A directed into the page and that in the outer conductor is 2.5 A directed out of the page. The distance from point C to point A is 0.0015 m; and the distance from C to B is 0.0030 m. The radii a and b of the conductors are 6.0 × 10-4 m and 1.9 × 10-3 m, respectively. -What is the magnitude and direction of the magnetic field at point A?

A charged particle is moving in a uniform, constant magnetic field. Which one of the following statements concerning the magnetic force exerted on the particle is false?

An electron is moving with a speed of 3.5 × 10⁵ m/s when it encounters a magnetic field of 0.60 T. The direction of the magnetic field makes an angle of 60.0° with respect to the velocity of the electron. What is the magnitude of the magnetic force on the electron?

A long, straight wire carries a current I. If the magnetic field at a distance d from the wire has magnitude B, what is the magnitude of the magnetic field at a distance 2d from the wire?

A rectangular loop has sides of length 0.06 m and 0.08 m. The wire carries a current of 10 A in the direction shown. The loop is in a uniform magnetic field of magnitude 0.2 T and directed in the positive x direction. What is the magnitude of the torque on the loop?

Two long, straight, parallel wires separated by a distance d carry currents in opposite directions as shown in the figure. The bottom wire carries a current of 6.0 A. Point C is at the midpoint between the wires and point O is a distance 0.50d below the 6-A wire as suggested in the figure. The total magnetic field at point O is zero tesla. -Determine the value of the current, I, in the top wire.

Two electrons are located in a region of space where the magnetic field is zero. Electron A is at rest; and electron B is moving westward with a constant velocity. A non-zero magnetic field directed eastward is then applied to the region. In what direction, if any, will each electron be moving after the field is applied?

Which one of the following statements concerning the magnetic force on a charged particle in a magnetic field is true?

An electron traveling due south enters a region that contains both a magnetic field and an electric field. The electric field lines point due west. It is observed that the electron continues to travel in a straight line due south. In which direction must the magnetic field lines point?

An overhead electric power line carries a maximum current of 125 A. What is the magnitude of the maximum magnetic field at a point 4.50 m directly below the power line?

Two long, straight wires separated by 0.10 m carry currents of 18 A and 6 A in the same direction as shown. -Determine the magnitude of the magnetic field at the point P.

A beam consisting of five types of ions labeled A, B, C, D, and E enters a region that contains a uniform magnetic field as shown in the figure below. The field is perpendicular to the plane of the paper, but its precise direction is not given. All ions in the beam travel with the same speed. The table below gives the masses and charges of the ions. Note: 1 mass unit = 1.67 × 10^-27 kg and e = 1.6 × 10^-19 C -Which ion falls at position 2?

Four long, straight wires are parallel to each other; and their cross-section forms a square. Each side of the square is 0.020 m as shown in the figure. If each wire carries a current of 8.0 A in the direction shown in the figure, determine the magnitude of the total magnetic field at P, the center of the square.

A wire is bent into the shape of a circle of radius r = 0.10 m and carries a 20.0-A current in the direction shown. -What is the direction of the magnetic field at the center of the loop?