Exam 26: Magnetic Field and Magnetic Forces

A charge is accelerated from rest through a potential difference V and then enters a uniform magnetic field oriented perpendicular to its path. The field deflects the particle into a circular arc of radius R. If the accelerating potential is tripled to 3V, what will be the radius of the circular arc?

A straight 15.0-g wire that is 2.00 m long carries a current of 8.00 A. This wire is aligned horizontally along the west-east direction with the current going from west to east. You want to support the wire against gravity using the weakest possible uniform external magnetic field. (a) Which way should the magnetic field point? (b) What is the magnitude of the weakest possible magnetic field you could use?

A vertical wire carries a current vertically upward in a region where the magnetic field vector points toward the north. What is the direction of the magnetic force on this current due to the field?

A particle with charge -5.00 C initially moves at = (1.00 î + 7.00 ĵ ) m/s. If it encounters a magnetic field Find the magnetic force vector on the particle.

A proton is first accelerated from rest through a potential difference V and then enters a uniform 0.750-T magnetic field oriented perpendicular to its path. In this field, the proton follows a circular arc having a radius of curvature of 1.84 cm. What was the potential difference V? (mproton = 1.67 × 10^-27 kg, e = 1.60 × 10^-19 C)

As shown in the figure, a small particle of charge q = -7.0 × 10^-6 C and mass m = 3.1 × 10^-12 kg has velocity v₀ = 9.4 × 10³ m/s as it enters a region of uniform magnetic field. The particle is observed to travel in the semicircular path shown, with radius R = 5.0 cm. Calculate the magnitude and direction of the magnetic field in the region.

An alpha particle is moving at a speed of 5.0 × 10⁵ m/s in a direction perpendicular to a uniform magnetic field of strength 0.040 T. The charge on an alpha particle is 3.2 × 10^-19 C and its mass is 6.6 × 10^-27 kg. (a) What is the radius of the path of the alpha particle? (b) How long does it take the alpha particle to make one complete revolution around its path?

A charged particle of mass 0.0020 kg is subjected to a 6.0 T magnetic field which acts at a right angle to its motion. If the particle moves in a circle of radius 0.20 m at a speed of 5.0 m/s, what is the magnitude of the charge on the particle?

An L-shaped metal machine part is made of two equal-length segments that are perpendicular to each other and carry a 4.50-A current as shown in the figure. This part has a total mass of 3.80 kg and a total length of 3.00 m, and it is in an external 1.20-T magnetic field that is oriented perpendicular to the plane of the part, as shown. What is the magnitude of the NET magnetic force that the field exerts on the part?

A rigid circular loop has a radius of 0.20 m and is in the xy-plane. A clockwise current I is carried by the loop, as shown. The magnitude of the magnetic moment of the loop is 0.75 A ∙ m². A uniform external magnetic field, B = 0.20 T in the positive x-direction, is present. (a) What is the current in the loop? (b) Find the magnitude of the magnetic torque exerted on the loop. (c) If the loop is released from rest, in what direction will points a and c initially move?

Three particles travel through a region of space where the magnetic field is out of the page, as shown in the figure. The electric charge of each of the three particles is, respectively,

A rectangular loop of wire carrying a 4.0-A current is placed in a magnetic field of 0.60 T. The magnitude of the torque acting on this wire when the plane of the loop makes a 30° angle with the field is measured to be 1.1 N ∙ m. What is the area of this loop?

A circular loop of diameter 10 cm, carrying a current of 0.20 A, is placed inside a magnetic field = 0.30 T ) The normal to the loop is parallel to a unit vector = -0.60 î - 0.80 ĵ. Calculate the magnitude of the torque on the loop due to the magnetic field.

An electron moving with a velocity = 5.0 × 107 m/s î enters a region of space where perpendicular electric and a magnetic fields are present. The electric field is = ĵ) What magnetic field will allow the electron to go through the region without being deflected?

An electron moving in the direction of the +x-axis enters a magnetic field. If the electron experiences a magnetic deflection in the -y direction, the direction of the magnetic field in this region points in the direction of the

A rigid rectangular loop, which measures 0.30 m by 0.40 m, carries a current of 5.5 A, as shown in the figure. A uniform external magnetic field of magnitude 2.9 T in the negative x direction is present. Segment CD is in the xz-plane and forms a 35° angle with the z-axis, as shown. Find the magnitude of the external torque needed to keep the loop in static equilibrium.