Exam 24: Magnetic Fields and Forces

Two long parallel wires carry currents of 20 A and 5.0 A in opposite directions. The wires are separated by 20 cm. At what point between the two wires do they produce the same strength magnetic field?

A rectangular coil, with corners labeled ABCD, has length L and width w. It is placed between the poles of a magnet, as shown in the figure. If there is a current I flowing through this coil in the direction shown, what is the direction of the force acting on section CD of this coil?

A charged particle moves with a constant speed through a region where a uniform magnetic field is present. If the magnetic field points straight upward, the magnetic force acting on this particle will be strongest when the particle moves

An electron moving in the +y direction, at right angles to a magnetic field, experiences a magnetic force in the -x direction. The direction of the magnetic field is in the

A long straight wire carrying a 4-A current is placed along the x-axis as shown in the figure. What is the magnitude of the magnetic field at a point P, located at y = 2 cm, due to the current in this wire? (μ₀ = 4π × 10^-7 T ∙ m/A)

How much current must pass through a 400-turn ideal solenoid that is 4.0 cm long to generate a 1.0-T magnetic field at the center? (μ₀ = 4π × 10^-7 T ∙ m/A)

A straight wire is carrying a current of 2.0 A. It is placed at an angle of 60° with respect to a magnetic field of strength 0.20 T. If the wire experiences a force of 0.40 N, what is the length of the wire?

Three particles travel through a region of space where the magnetic field is out of the page, as shown in the figure. What are the signs of the charges of these three particles?

The magnetic field due to the current in a long, straight wire is 8.0 μT at a distance of 4.0 cm from the center of the wire. What is the current in the wire? (μ₀ = 4π × 10^-7 T ∙ m/A)

An ideal solenoid is wound with 470 turns on a wooden form that is 4.0 cm in diameter and 50 cm long. The windings carry a current in the sense shown in the figure. The current produces a magnetic field of magnitude $4.1 \mathrm { mT } \text {, }$ at the center of the solenoid. What is the current I in the solenoid windings? (?₀ = 4? × 10^-7 T ? m/A)

A 2.0-m straight wire carrying a current of 0.60 A is oriented parallel to a uniform magnetic field of 0.50 T. What is the magnitude of the magnetic force on it?

What is the strength of the magnetic field at the center of a circular loop of wire of diameter 8.0 cm when a current of 2.0 A flows in the wire? (?₀ = 4? × 10^-7 T ? m/A)

A charged particle of mass 0.0040 kg is subjected to a $4.0 - \mathrm { T }$ magnetic field which acts at a right angle to its motion. If the particle moves in a circle of radius $0.10 \mathrm {~m}$ at a speed of $2.0 \mathrm {~m} / \mathrm { s } \text {, }$ what is the magnitude of the charge on the particle?

Two long parallel wires placed side-by-side on a horizontal table carry identical size currents in opposite directions. The wire on your right carries current directly toward you, and the wire on your left carries current directly away from you. From your point of view, the magnetic field at a point exactly midway between the two wires

Two long parallel wires separated by 7.5 cm each carry 3.3 A in opposite directions. (?₀ = 4? × 10^-7 T ? m/A) (a)What magnetic force per length acts on each of the wires? Is it attractive or repulsive? (b)Find the magnitude of the magnetic field midway between the two wires.

A charged particle moving along the +x-axis enters a uniform magnetic field pointing along the +z-axis. Because of an electric field along the +y-axis, the charge particle does not change velocity. What is the sign of this particle?

A current-carrying loop of wire lies flat on a horizontal tabletop. When viewed from above, the current moves around the loop in a counterclockwise sense. For points on the tabletop outside the loop, the magnetic field lines caused by this current

In the figure, the two long straight wires are separated by a distance of $d = 0.40 \mathrm {~m} .$ The currents are $I _ { 1 }$ = 1.0 A to the right in the upper wire and $I _ { 2 }$ = 8.0 A to the left in the lower wire. What are the magnitude and direction of the magnetic field at point P, that is a distance $d / 2 = 0.20 \mathrm {~m}$ below the lower wire? (?₀ = 4? × 10^-7 T ? m/A)

A wire in the shape of an "M" lies in the plane of the paper. It carries a current of 2.0 A, flowing from A to E, as shown in the figure. It is placed in a uniform magnetic field of 0.75 T in the same plane, directed as shown on the right side of the figure. The figure indicates the dimensions of the wire. Note that AB is parallel to DE and to the baseline from which the magnetic field direction is measured. What are the magnitude and direction of the force acting on section AB of this wire?

Consider an ideal solenoid of length L, N windings, and radius b (L is much longer than b). A current I is flowing through the wire windings. If the length of the solenoid becomes twice as long (to 2L), but all other quantities remained the same, the magnetic field inside the solenoid will