---
title: "A thin, rigid wire carries a constant current \\(I\\) and is bent to form a closed flat loop in a plane. The loop consists of a semicircle of radius \\(R\\) and a straight wire segment of length \\(2R\\) along the diameter connecting the endpoints of the semicircle. Point \\(P\\) is located at the center of curvature of the semicircle. Which of the following expressions represents the magnitude of the magnetic field at point \\(P\\)?"
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url: "https://nerd-notes.com/ubq/118578/"
date_modified: "2026-08-04T08:11:25+00:00"
---

# A thin, rigid wire carries a constant current \(I\) and is bent to form a closed flat loop in a plane. The loop consists of a semicircle of radius \(R\) and a straight wire segment of length \(2R\) along the diameter connecting the endpoints of the semicircle. Point \(P\) is located at the center of curvature of the semicircle. Which of the following expressions represents the magnitude of the magnetic field at point \(P\)?

A thin, rigid wire carries a constant current \(I\) and is bent to form a closed flat loop in a plane. The loop consists of a semicircle of radius \(R\) and a straight wire segment of length \(2R\) along the diameter connecting the endpoints of the semicircle. Point \(P\) is located at the center of curvature of the semicircle. Which of the following expressions represents the magnitude of the magnetic field at point \(P\)?

![A planar diagram showing a closed wire loop in two dimensions. The loop consists of an upper semicircle of radius R and a flat straight horizontal segment along the bottom of length 2R connecting the two ends of the semicircle. Point P is marked with a filled dot at the center of curvature of the semicircle, sitting at the midpoint of the horizontal straight segment. An arrow along the semicircle points counterclockwise to show current I flowing around the loop, with another arrow on the straight segment pointing to the right. A dashed radial line connects point P to the top of the semicircle and is labeled R. No other labels, lines, text, or axes appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1785831085-h1qRlK.jpg)

- **A.** \(\dfrac{\mu_0 I}{2\pi R}\)
- **B.** \(\dfrac{\mu_0 I}{2R}\)
- **C.** \(\dfrac{\mu_0 I}{4R}\)
- **D.** \(\dfrac{\mu_0 I}{4R} + \dfrac{\mu_0 I}{2\pi R}\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/118578/*