Question

For questions 1-3 use the figure below and give the direction of the magnetic force on the charged particle (black dot). Note that for 1 and 2 the magnetic field is into the page and for 3 it is to the right. Note also the sign of the charge on the particle is given in parentheses (+) or (-). What is the direction of the force on particle (1)? What is the direction of the force on particle (2)? What is the direction of the force on particle (3) ?

Answer 1

Concepts and reason

The concept that is used to solve this problem is right-hand palm rule.

Initially, calculate the direction of the force on the positive and negative charged particle when a magnetic field is into the page. Later, calculate the direction of the force on the negative charge particle when a magnetic field is from left to right.

Fundamentals

Write the right-hand palm rule to calculate the direction of the force on the moving charged particle in the magnetic field.

Right-hand palm rule states that if thumb shows the direction of the velocity of positive charged particle and fingers shows the direction of magnetic field then perpendicular to the palm shows the direction of the force on the moving particle.

(1)

Consider the direction of the force on the moving charged particle in the magnetic field and calculate by using right-hand palm rule. In the figure (1), the direction of magnetic field is into the page (or screen) and velocity of moving particle is down to up. Use the right-hand palm rule to get the direction of the force on the charged particle to be from left to right.

Consider the direction of the force as shown in the figure (1).

Here, ${\bf{B}}$ is the magnetic field into the page, ${\bf{F}}$ is the force on the charged particle, and ${\bf{v}}$ is the velocity of charged particle.

(2)

Consider the direction of the force on the moving charged particle in the magnetic field and calculate it by using right-hand palm rule. In the figure (2), the direction of magnetic field is into the page (or screen) and velocity of moving particle is up to down. Use the right-hand palm rule to get the direction of the force on the positive charge particle to be from left to right.

Draw the direction of the force as shown in the figure (2).

(3)

Consider the direction of the force on the moving charged particle in the magnetic field and calculate it by using right-hand palm rule. In the figure (3), the direction of magnetic field is from left to right and velocity of moving particle is up to down. Use the right-hand palm rule to get the direction of the force on the negatively charged particle to be into the page (or screen).

Draw the direction of the force as shown in the figure (3).

Ans: Part 1

The direction of the force on the negative charge particle is from left to right.

Part 2

The direction of the force on the positive charge particle is from left to right.

Part 3

The direction of the force on the negatively charged particle is into the page (or screen).