Lesson: The Magnetic Field due to a Current in a Solenoid Physics

In this lesson, we will learn how to calculate the magnetic field produced by a current in a solenoid.

Lesson Plan

Lesson Video

Video Thumbnail

Lesson Explainer

Lesson Worksheet


A length of wire is formed into a solenoid with 𝑛 turns of wire per millimeter. The wire carries a constant current 𝐼. As a result, a magnetic field of strength 𝐡 can be measured at the center of the solenoid. Which of the following changes to the system would increase the magnetic field strength at the center of the solenoid, assuming everything else remains constant?


A solenoid is formed of a wire that carries a constant current of 0.16 A. The magnetic field at the center of the solenoid is measured to be 3.8Γ—10οŠͺ T. Calculate the number of turns of wire per centimeter of the solenoid’s length, rounding to the nearest whole number of turns. Use a value of 4πœ‹Γ—10 Tβ‹…m/A for πœ‡οŠ¦.


A wire is given the form of a solenoid S that has 400 turns and a length of 𝑙. The current in S is 𝐼 and the strength of the magnetic field produced by S at its center is 𝐡. A second wire is used to form a solenoid S that has 150 turns. S and S are connected end to end to form a solenoid S. The spacing of the turns of S is adjusted until the length of S is 𝑙 and the turns of S are equidistant from each other. The turns of S are equal in radius to the turns of S. The current in S is 𝐼, and the strength of the magnetic field produced by S at its center is 𝐡. Which of the following describes the relationship between 𝐡 and 𝐡?

Nagwa uses cookies to ensure you get the best experience on our website. Learn more about our Privacy Policy.