22.4 Magnetic field strength: force on a moving charge in a magnetic  (Page 2/7)

A proton moves in the – x -direction and encounters a uniform magnetic field pointing in the + x -direction. In what direction is the resulting magnetic force on the proton?

1. The proton experiences no magnetic force.
2. + x -direction
3. − y -direction
4. + y -direction

A proton moves with a speed of 240 m/s in the + x -direction into a region of a 4.5-T uniform magnetic field directed 62° above the + x -direction in the x , y -plane. Calculate the magnitude of the magnetic force on the proton.

If a charged particle moves in a straight line through some region of space, can you say that the magnetic field in that region is necessarily zero?

What is the direction of the magnetic force on a positive charge that moves as shown in each of the six cases shown in [link] ?

Repeat [link] for a negative charge.

What is the direction of the velocity of a negative charge that experiences the magnetic force shown in each of the three cases in [link] , assuming it moves perpendicular to $\mathbf{\text{B}}\mathrm{?}$

Repeat [link] for a positive charge.

What is the direction of the magnetic field that produces the magnetic force on a positive charge as shown in each of the three cases in the figure below, assuming $\mathbf{\text{B}}$ is perpendicular to $\mathbf{\text{v}}$ ?

Repeat [link] for a negative charge.

What is the maximum force on an aluminum rod with a $0\text{.}\text{100}\text{-μC}$ charge that you pass between the poles of a 1.50-T permanent magnet at a speed of 5.00 m/s? In what direction is the force?

(a) Aircraft sometimes acquire small static charges. Suppose a supersonic jet has a $0\text{.}\text{500}\text{-μC}$ charge and flies due west at a speed of 660 m/s over the Earth’s south magnetic pole, where the $8\text{.}\text{00}\times {\text{10}}^{-5}\text{-T}$ magnetic field points straight up. What are the direction and the magnitude of the magnetic force on the plane? (b) Discuss whether the value obtained in part (a) implies this is a significant or negligible effect.

(a) A cosmic ray proton moving toward the Earth at $\text{5.00}\times {\text{10}}^7\text{m/s}$ experiences a magnetic force of $1\text{.}\text{70}\times {\text{10}}^{-\text{16}}\text{N}$ . What is the strength of the magnetic field if there is a $\text{45º}$ angle between it and the proton’s velocity? (b) Is the value obtained in part (a) consistent with the known strength of the Earth’s magnetic field on its surface? Discuss.

An electron moving at $4\text{.}\text{00}\times {\text{10}}^3\text{m/s}$ in a 1.25-T magnetic field experiences a magnetic force of $1\text{.}\text{40}\times {\text{10}}^{-\text{16}}\text{N}$ . What angle does the velocity of the electron make with the magnetic field? There are two answers.

(a) A physicist performing a sensitive measurement wants to limit the magnetic force on a moving charge in her equipment to less than $1\text{.}\text{00}\times {\text{10}}^{-\text{12}}\mathrm{N}$ . What is the greatest the charge can be if it moves at a maximum speed of 30.0 m/s in the Earth’s field? (b) Discuss whether it would be difficult to limit the charge to less than the value found in (a) by comparing it with typical static electricity and noting that static is often absent.