Q: Which of the following correctly expresses the magnetic force on a charged particle moving with velocity $$\vec{v} in a $$magnetic field $$\vec{B}$$?

$$\vec{F}_B = q \vec{v} \times \vec{B}$$

Q: Which of the following is a correct statement about the discovery of the electron in Thomson’s experiment?

The electron's charge is $$e = 1.602176634 \times 10$$^{-19}$$ C

Q: A particle moves in a region with both electric and magnetic fields. The net force is given by:

$$\vec{F} = q (\vec{E} + \vec{v} \times \vec{B})$$

Question 1

Which of the following correctly expresses the magnetic force on a charged particle moving with velocity $$\vec{v} in a $$magnetic field $$\vec{B}$$?

Accepted Answer

$$\vec{F}_B = q \vec{v} 	imes \vec{B}$$

Question 2

A proton moves parallel to a uniform magnetic field $$\vec{B}. $$What is the direction of the magnetic force acting on the proton?

Accepted Answer

No force acts on the proton

Question 3

A negative charge moves to the right in a region where the magnetic field points into the page. What is the direction of the magnetic force on the charge?

Accepted Answer

Downward

Question 4

Which equation describes the work done by the magnetic force on a moving charge?

Accepted Answer

$$dW = 0$$

Question 5

A particle of mass $$m$$ and charge $$q$$ moves in a circle of radius $$R in a $$uniform magnetic field $$B. $$What is the expression for the radius $$R$$?

Accepted Answer

$$R = \frac{mv}{|q|B}$$

Question 6

In a velocity selector, charged particles pass through perpendicular electric and magnetic fields. If the net force is zero, what is the speed of the particles?

Accepted Answer

$$v = \frac{E}{B}$$

Question 7

Which of the following is NOT a consequence of the magnetic force acting on a charged particle?

Accepted Answer

The particle's speed changes

Question 8

A beam of singly ionized uranium atoms ($$^{235}U$$ and $$^{238}U) $$enters a mass spectrometer. Which isotope will have a larger radius of curvature?

Accepted Answer

$$^{238}U$$

Question 9

If the magnetic field strength in a mass spectrometer is increased, what happens to the spacing between where $$^{235}U$$ and $$^{238}U$$ ions strike the detector?

Accepted Answer

The spacing decreases

Question 10

Which of the following is a correct statement about the discovery of the electron in Thomson’s experiment?

Accepted Answer

The electron's charge is $$e = 1.602176634 	imes 10$$^{-19}$$ C

Question 11

Which of the following is the correct expression for centripetal acceleration?

Accepted Answer

$$a_c = \frac{v^2$}{R}$$

Question 12

A particle moves in a region with both electric and magnetic fields. The net force is given by:

Accepted Answer

$$\vec{F} = q (\vec{E} + \vec{v} 	imes \vec{B})$$

Question 13

Which of the following statements about the work done by the magnetic force is correct?

Accepted Answer

The magnetic force does no work on the charge

Question 14

A particle with charge $$q$$ and mass $$m$$ moves with velocity $$v$$ perpendicular to a uniform magnetic field $$B. $$What is the expression for the magnetic force?

Accepted Answer

$$F = qvB$$

Question 15

Which of the following is a correct statement about isotopes discovered using mass spectrometers?

Accepted Answer

Isotopes have the same number of protons

Question 16

A particle moves in a circle in a magnetic field. What provides the centripetal force?

Accepted Answer

Magnetic force

Question 17

Which of the following is the correct formula for the kinetic energy of a particle?

Accepted Answer

$$K = \frac{1}{2}mv^2$

Question 18

In a velocity selector, what is the relationship between the electric and magnetic forces for a particle to pass through undeflected?

Accepted Answer

$$qE = qvB$$

Question 19

Which of the following is NOT a property of antimatter compared to matter?

Accepted Answer

Different number of protons

Guidance on Magnetic Force Direction for Charges in a Magnetic Field

Guida di studio - Domande di pratica

Study guide - Flashcard