Charge in a Magnetic Field question

In summary, the discussion is about two similar questions, one from a previous exam and one from a sample test, and how to determine the i or j component in each of them. The formula sheet is referenced and the use of a coordinate system is mentioned. It is explained that the direction of the force on a positive charge is the same as the direction of the induced current at the position of the charge. The options for the direction of the current are limited by the clockwise or counterclockwise flow. The question asks if the sign can be determined based on the direction of the current flow.
  • #1
Lonewolf393
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Homework Statement


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These are two similar questions, one from my previous exam and one from a sample test my teacher provided. I understand how to work the problem, but my question is how is the i or j component decided in each of these?

Homework Equations



From our formula sheet...
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The Attempt at a Solution


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  • #2
There is a coordinate system provided that gives the direction of the unit vectors. The direction of the force on charge q (assuming it is positive) is the same as the direction of the induced current at the position of the charge if the dotted circle were a circular metal loop. The induced current can either be clockwise or counterclockwise. This eliminates all the ## \hat{j}## options in the first picture and all the ##\hat{i}## options in the second picture. The sign depends on whether you have clockwise or counterclockwise current flow. Can you figure that out?
 

FAQ: Charge in a Magnetic Field question

What is the relationship between charge and magnetic field?

The relationship between charge and magnetic field is that a charged particle moving through a magnetic field will experience a force perpendicular to both the direction of its motion and the direction of the magnetic field. This force is known as the Lorentz force and is given by the equation F = qv x B, where q is the charge of the particle, v is its velocity, and B is the magnetic field.

How does the direction of the magnetic field affect a charged particle?

The direction of the magnetic field will determine the direction of the force experienced by a charged particle. If the magnetic field is perpendicular to the particle's motion, the force will be perpendicular to both the field and the particle's velocity, causing the particle to move in a circular path. If the magnetic field is parallel to the particle's motion, there will be no force acting on the particle.

What is the difference between a uniform and non-uniform magnetic field?

A uniform magnetic field has a constant magnitude and direction throughout the entire field. This means that a charged particle will experience the same force at all points within the field. A non-uniform magnetic field has varying magnitudes and/or directions at different points within the field, causing the force on a charged particle to vary as well.

How does the strength of the magnetic field affect the force on a charged particle?

The strength of the magnetic field, represented by the symbol B, directly affects the force experienced by a charged particle. The stronger the magnetic field, the greater the force on the particle will be. This can be seen in the equation F = qv x B, where B is in the denominator, meaning that as B increases, the force increases as well.

What are some real-world applications of the relationship between charge and magnetic field?

Some real-world applications of the relationship between charge and magnetic field include electric motors, particle accelerators, magnetic resonance imaging (MRI) machines, and generators. In these devices, the interaction between charged particles and magnetic fields is utilized to produce motion, generate electricity, or create images of the human body.

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