# Apply the ampere's law to the infinite solenoid

• newton1

#### newton1

how to apply the ampere's law to the infinite solenoid...
how we find the equation for the magnetic field ??
who can help...

Greetings Newton1 !

I suggest you check the links at the "napster"
thread at the top, such basic definitions and
explanations are relativly easy to find.

Live long and prosper.

re - "how to apply the ampere's law to the infinite solenoid...
how we find the equation for the magnetic field ??
who can help..."

Construct an amperian loop around the windings and along the axis. Hard to describe - easier to draw.

Let the solenoid be

<-----<-----<--B--<-----<-----<--

------------
| |
--------|----------|------------/
------------ /
------>------->-------->---->-/
/
----------------------------/

Then integrate around the loop. It's been years since I've done this stuff so let me know how you do. This should start yoiu off. Keep in mind the number of turns per unit length in the solebnoid and the current in the filiment. I think you may assume that the field inside the solenoid is uniform. The answer should come easy after that.

Pete

yes...i get it
and thank:)

## 1. What is ampere's law?

Ampere's law is a fundamental law in electromagnetism that relates the magnetic field around a closed loop to the electric current passing through that loop. It is named after the French physicist André-Marie Ampère.

## 2. How is ampere's law applied to an infinite solenoid?

Ampere's law can be applied to an infinite solenoid by considering a closed loop passing through the center of the solenoid. The law states that the integral of the magnetic field around this loop is equal to the product of the current passing through the solenoid and the number of turns per unit length of the solenoid.

## 3. What is the magnetic field inside an infinite solenoid?

The magnetic field inside an infinite solenoid is uniform and directed along the axis of the solenoid. It can be calculated using the equation B = μ₀nI, where B is the magnetic field, μ₀ is the permeability of free space, n is the number of turns per unit length, and I is the current passing through the solenoid.

## 4. How does the magnetic field outside an infinite solenoid behave?

Outside the solenoid, the magnetic field is negligible due to the cancellation of the magnetic fields created by the individual turns of the solenoid. This results in a magnetic field that is almost zero outside the solenoid.

## 5. What are some practical applications of ampere's law and the infinite solenoid?

Ampere's law and the infinite solenoid have various practical applications, such as in the design of electromagnets and inductors for electronic devices. They are also used in medical imaging techniques like magnetic resonance imaging (MRI) and in particle accelerators. Additionally, the concept of an infinite solenoid is used in theoretical models for understanding and predicting the behavior of magnetic fields in different systems.