Exam 20: Magnetic Fields and Forces

A deuteron, with the same charge but twice the mass of a proton, moves with a speed of 6.0 * 10⁵ m/s perpendicular to a uniform magnetic field of 0.20 T. Which of the paths described below would it follow? (q_p = 1.6 * 10 ^{- 19} C and m_d = 3.34 *10 ^{- 27} kg)

An electron moves through a region of crossed electric and magnetic fields. The electric field E = 3200 V/m and is directed straight down. The magnetic field B = 0.80 T and is directed to the left. For what velocity v of the electron into the paper will the electric force exactly cancel the magnetic force?

At the Fermilab accelerator in Weston, Illinois, singly-charged ions with momentum 3.2 *10 ^{- 16} kg.m/s are held in a circular orbit of radius 1 km by an upward magnetic field. What B-field must be used to maintain the ions in this orbit? (q_ion = 1.6 *10 ^{- 19} C)

Consider two long, straight parallel wires, each carrying a current I. If the currents are flowing in the same direction:

A proton and an alpha particle are moving perpendicular to a uniform magnetic field with the same speed. If the velocity of the proton is at an angle of 20° with respect to the magnetic field direction, at what angle to the magnetic field direction would the alpha particle be moving if it experiences the same magnitude acceleration as the proton? The alpha particle has 4 times the mass of the proton and twice its charge.

Niobium metal becomes a superconductor (with electrical resistance equal to zero) when cooled below 9 K. If superconductivity is destroyed when the surface magnetic field exceeds 0.100 T, determine the maximum current a 2.00-mm diameter niobium wire can carry and remain superconducting. (µ₀ = 4 $\pi$ *10^-7 T.m/A)

A horizontal wire of length 3.6 m carries a current of 6.0 A and is oriented so that the current direction is 50° S of W. The Earth's magnetic field is due north at this point and has a strength of 0.14 *10 ^{- 4} T. What is the direction of the force on the wire?

The direction of the force on a current carrying wire located in an external magnetic field is which of the following?

A superconducting solenoid is to be designed to generate a magnetic field of 2.50 T. If the solenoid winding has 1000 turns/m, what is the required current? (µ₀ = 4 $\pi$ *10 ^{- 7} T.m/A)

The magnetic field of the Earth is believed responsible for which of the following?

A horizontal wire of length 3.6 m carries a current of 6.0 A and is oriented so that the current direction is 50° S of W. The Earth's magnetic field is due north at this point and has a strength of 0.14 * 10^-4 T. What is the size of the force on the wire?

A 100-m long wire carrying a current of 4.0 A will be accompanied by a magnetic field of what strength at a distance of 0.040 m from the wire? (magnetic permeability in empty space µ₀ = 4 $\pi$ *10 ^{- 7} T.m/A)

A square loop of wire has a current going around it. The magnetic field from the current on each side of the loop results in a magnetic force on the wire on the opposite side. Each resulting magnetic force on the opposite side wire

In a mass spectrometer, an ion will have a smaller radius for its circular path if:

There is a magnetic force on a particle. It is possible that the particle is:

A circular loop carrying a current of 3.0 A is oriented in a magnetic field of 0.35 T. The loop has an area of 0.24 m² and is mounted on an axis, perpendicular to the magnetic field, which allows the loop to rotate. What is the torque on the loop when its plane is oriented at a 50° angle to the field?

A proton is released such that it has an initial speed of 5.0 *10⁵ m/s from left to right across the page. A magnetic field of 1.2 T is present at an angle of 30° to the horizontal direction (or positive x axis). What is the magnitude of the force experienced by the proton? (q_p = 1.6 *10^-19 C)