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| 184_notes:moving_q [2018/07/03 03:51] – [Magnetic Field Vectors] curdemma | 184_notes:moving_q [2020/08/23 21:26] – dmcpadden |
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| Section 17.3 in Matter and Interactions (4th edition) | Section 17.3 in Matter and Interactions (4th edition) |
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| [[184_notes:rhr|Next Page: Right Hand Rule]] | /*[[184_notes:rhr|Next Page: Right Hand Rule]] |
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| [[184_notes:mag_interaction|Previous Page: Magnetic Interaction]] | [[184_notes:mag_interaction|Previous Page: Magnetic Interaction]]*/ |
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| ===== Moving Charges Make Magnetic Fields ===== | ===== Moving Charges Make Magnetic Fields ===== |
| * **Direction - Cross Product** - the final piece to this equation is the [[183_notes:cross_product|cross product]] between $\vec{v}$ and $\hat{r}$ or between $\vec{v}$ and $\vec{r}$ depending on how you wrote the equation. The cross product is a way to [[184_notes:math_review#vector_multiplication|multiply vectors]] that gives a perpendicular vector as the product. You have seen the cross product before when we were talking about [[184_notes:e_flux|area vectors]] or you may remember the cross product from calculus or learning [[183_notes:torque|torque]] in mechanics. Because of how the cross product works, this means that the **magnetic field is perpendicular to both the velocity of the moving charge and the separation vector**. So for a charge moving in a straight line, the magnetic field creates a curling field (in ring) around the charge. You can always use the [[183_notes:cross_product|determinant method]] to calculate the cross product and thus the direction of the magnetic field, but we will also make use of the Right Hand Rule as tool to figure out the direction of the magnetic field. | * **Direction - Cross Product** - the final piece to this equation is the [[183_notes:cross_product|cross product]] between $\vec{v}$ and $\hat{r}$ or between $\vec{v}$ and $\vec{r}$ depending on how you wrote the equation. The cross product is a way to [[184_notes:math_review#vector_multiplication|multiply vectors]] that gives a perpendicular vector as the product. You have seen the cross product before when we were talking about [[184_notes:e_flux|area vectors]] or you may remember the cross product from calculus or learning [[183_notes:torque|torque]] in mechanics. Because of how the cross product works, this means that the **magnetic field is perpendicular to both the velocity of the moving charge and the separation vector**. So for a charge moving in a straight line, the magnetic field creates a curling field (in ring) around the charge. You can always use the [[183_notes:cross_product|determinant method]] to calculate the cross product and thus the direction of the magnetic field, but we will also make use of the Right Hand Rule as tool to figure out the direction of the magnetic field. |
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| Together, these pieces tell you how the electric field from a point charge changes in space. The main take away here is: **the magnetic field is created by //moving// charges, points in a perpendicular direction, and can be calculated for every point in space around the charge**. The examples below show a few instances of how to calculate the magnetic field and how to use the Right Hand Rule to figure out the direction. | Together, these pieces tell you how the magnetic field from a point charge changes in space. The main take away here is: **the magnetic field is created by //moving// charges, points in a perpendicular direction, and can be calculated for every point in space around the charge**. The examples below show a few instances of how to calculate the magnetic field and how to use the Right Hand Rule to figure out the direction. |
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| ==== Magnetic Field Vectors ==== | ==== Magnetic Field Vectors ==== |