Translated 9.2.10-9.2.17
en/9.2.13.md
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| + | <meta name="description" content="A long straight wire with current I has a section in the form of a semicircle of radius R. Determine the magnetic field induction at the center of the semicircle."> | ||
| + | <meta name="author" content="Aliaksandr Melnichenka"> | ||
| + | <meta name="date" content="2023-10" scheme="YYYY-MM"> | ||
| + | <meta property="og:title" content="A long straight wire with current I has a section in the form of a semicircle of radius R. Determine the magnetic field induction at the center of the semicircle."> | ||
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| + | <title>A long straight wire with current I has a section in the form of a semicircle of radius R. Determine the magnetic field induction at the center of the semicircle.</title> | ||
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| + | <body style=""> | ||
| + | <header style="text-align:center;"> | ||
| + | <a href="../../" style="text-decoration: none;"> | ||
| + | <div id="logo"> | ||
| + | <span><img src="../../img/book.png"></span><span>Savchenko Solutions</span> | ||
| + | </div> | ||
| + | </a> | ||
| + | <p class="author"> | ||
| + | Solutions of Savchenko Problems in Physics <br> | ||
| + | <i><b>knowledge must be free</b></i> | ||
| + | </p> | ||
| + | </header> | ||
| + | |||
| + | <h3 id="back-link"><a href="../../#9.2">$\leftarrow$Back</a></h3> | ||
| + | |||
| + | <h3> Statement </h3> | ||
| + | <p> | ||
| + | $9.2.13.$ A long straight wire with current $I$ has a section in the form of a semicircle of radius $R$. Determine the magnetic field induction at the center of the semicircle. | ||
| + | </p> | ||
| + | <center> | ||
| + | <figure> | ||
| + | <img src="https://savchenkosolutions.com/9/9.2.13/statement.png" | ||
| + | loading="lazy" width="230" /> | ||
| + | <figcaption> | ||
| + | For problem $9.2.13$ | ||
| + | </figcaption> | ||
| + | </figure> | ||
| + | </center> | ||
| + | <p> | ||
| + | </p> | ||
| + | |||
| + | <h3>Solution</h3> | ||
| + | <p> | ||
| + | Let's write down the expression for the induction of a section of wire | ||
| + | $$ d\vec B = \frac{\mu_0 [\vec{(Idx)}\times \vec{R}]}{4\pi R^3} $$ | ||
| + | We find the modulus of the vector $d\vec B$ by transforming the vector product | ||
| + | $$ dB = \frac{\mu_0 Idx}{4\pi R^2}\sin\alpha $$ | ||
| + | Where $\alpha$ is the angle between the radius vector and the direction of the current element. Given that they coincide, then $\alpha = 0$: | ||
| + | $$ \sin\alpha = 0\Rightarrow dB = 0 $$ | ||
| + | For a straight section of wire, then such a design creates a field similar to the field of the semicircle, which we already calculated in <a href="../9.2.11">9.2.11</a> | ||
| + | $$ \boxed{B = \frac{\mu_0 I}{4R}} $$ | ||
| + | |||
| + | </p> | ||
| + | |||
| + | <h4>Answer</h4> | ||
| + | <p> | ||
| + | $$B=\frac{\mu_0 I}{4R}$$ | ||
| + | </p> | ||
| + | <p style="text-align: right; font-style: italic; font-size: 14;"> | ||
| + | Andrei Yersh<br> | ||
| + | </p> | ||
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| @@ -0,0 +1,100 @@ | |||
| <!DOCTYPE html> | |||
| <html lang="en"> | |||
| <head> | |||
| <meta charset="utf-8"> | |||
| <meta name="viewport" content="width=device-width, initial-scale=1.0"> | |||
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| <meta name="keywords" content="Savchenko Problems in Physics, Savchenko solutions, physics problems, physics olympiad preparation, IPhO, Jaan Kalda"> | |||
| <meta name="description" content="A long straight wire with current I has a section in the form of a semicircle of radius R. Determine the magnetic field induction at the center of the semicircle."> | |||
| <meta name="author" content="Aliaksandr Melnichenka"> | |||
| <meta name="date" content="2023-10" scheme="YYYY-MM"> | |||
| <meta property="og:title" content="A long straight wire with current I has a section in the form of a semicircle of radius R. Determine the magnetic field induction at the center of the semicircle."> | |||
| <meta property="og:image" content="img/logo.png"> | |||
| <meta property="og:description" content="A long straight wire with current I has a section in the form of a semicircle of radius R. Determine the magnetic field induction at the center of the semicircle."> | |||
| <meta name="yandex-verification" content="6cfda41f74038368"> | |||
| <title>A long straight wire with current I has a section in the form of a semicircle of radius R. Determine the magnetic field induction at the center of the semicircle.</title> | |||
| <link rel="stylesheet" href="https://savchenkosolutions.com/css/css-latex/style.css"> | |||
| <link rel="icon" href="https://savchenkosolutions.com/img/logo.png" type="image/png"> | |||
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| }, | |||
| showProcessingMessages: false, | |||
| messageStyle: 'none' | |||
| }); | |||
| </script> | |||
| </head> | |||
| <body style=""> | |||
| <header style="text-align:center;"> | |||
| <a href="../../" style="text-decoration: none;"> | |||
| <div id="logo"> | |||
| <span><img src="../../img/book.png"></span><span>Savchenko Solutions</span> | |||
| </div> | |||
| </a> | |||
| <p class="author"> | |||
| Solutions of Savchenko Problems in Physics <br> | |||
| <i><b>knowledge must be free</b></i> | |||
| </p> | |||
| </header> | |||
| <h3 id="back-link"><a href="../../#9.2">$\leftarrow$Back</a></h3> | |||
| <h3> Statement </h3> | |||
| <p> | |||
| $9.2.13.$ A long straight wire with current $I$ has a section in the form of a semicircle of radius $R$. Determine the magnetic field induction at the center of the semicircle. | |||
| </p> | |||
| <center> | |||
| <figure> | |||
| <img src="https://savchenkosolutions.com/9/9.2.13/statement.png" | |||
| loading="lazy" width="230" /> | |||
| <figcaption> | |||
| For problem $9.2.13$ | |||
| </figcaption> | |||
| </figure> | |||
| </center> | |||
| <p> | |||
| </p> | |||
| <h3>Solution</h3> | |||
| <p> | |||
| Let's write down the expression for the induction of a section of wire | |||
| $$ d\vec B = \frac{\mu_0 [\vec{(Idx)}\times \vec{R}]}{4\pi R^3} $$ | |||
| We find the modulus of the vector $d\vec B$ by transforming the vector product | |||
| $$ dB = \frac{\mu_0 Idx}{4\pi R^2}\sin\alpha $$ | |||
| Where $\alpha$ is the angle between the radius vector and the direction of the current element. Given that they coincide, then $\alpha = 0$: | |||
| $$ \sin\alpha = 0\Rightarrow dB = 0 $$ | |||
| For a straight section of wire, then such a design creates a field similar to the field of the semicircle, which we already calculated in <a href="../9.2.11">9.2.11</a> | |||
| $$ \boxed{B = \frac{\mu_0 I}{4R}} $$ | |||
| </p> | |||
| <h4>Answer</h4> | |||
| <p> | |||
| $$B=\frac{\mu_0 I}{4R}$$ | |||
| </p> | |||
| <p style="text-align: right; font-style: italic; font-size: 14;"> | |||
| Andrei Yersh<br> | |||
| </p> | |||
| <footer class="row container"> | |||
| <br> | |||
| <p> | |||
| <small> © <strong>Savchenko Solutions</strong>, 2023-2024 <br></small> | |||
| </p> | |||
| <p> | |||
| <small>All rights belong to the authors. <br> Commercial use of materials - with the written permission of the authors. <br> alex@savchenkosolutions.com <br></small> | |||
| </p> | |||
| </footer> | |||
| </body> | |||
| </html> | |||