# Current in an infinite current sheet

• chipotleaway
In summary, an infinite current sheet is a theoretical construct used in physics to model an infinitely thin sheet with a constant and uniform flow of electric current. The current is distributed evenly across its surface, making the current density constant at any point on the sheet. While it cannot exist in reality, it can be used as an approximation for certain physical systems. The magnetic field produced by an infinite current sheet is perpendicular to the sheet and points in the direction of the current flow, affecting its surroundings by interacting with other magnetic fields and inducing currents in nearby conductors.
chipotleaway
Suppose we have a infinite current sheet of surface density $\sigma$ and apply Ampere’s law to find the magnetic field. Using a rectangular loop of side lengths L, why would the enclosed current be $I=\sigma L$? Doesn't this imply the RHS has units of $\frac{Q}{m}$?

Shouldn't we be looking at this: $I=\frac{dQ}{dt}=\sigma \frac{dA}{dt}$?

A surface current density has units of A/m in the SI system. Multiplying that by length (units of m) gives current (units of A).

1 person

## 1. What is an infinite current sheet?

An infinite current sheet is a theoretical construct used in physics to model an infinitely thin sheet with a constant and uniform flow of electric current. It is often used as a simplification in calculations and is considered to have an infinite length and width, but a negligible thickness.

## 2. How is the current in an infinite current sheet distributed?

The current in an infinite current sheet is distributed evenly across its entire surface. This means that at any point on the sheet, the current density is constant and does not vary with position.

## 3. Can an infinite current sheet exist in reality?

No, an infinite current sheet cannot exist in reality as it is a theoretical construct. However, it can be used as an approximation for certain physical systems, such as a long straight wire or a very thin strip of conducting material.

## 4. What is the direction of the magnetic field produced by an infinite current sheet?

The magnetic field produced by an infinite current sheet is perpendicular to the sheet and points in the direction of the current flow. This means that the magnetic field lines are parallel to the sheet and do not intersect it.

## 5. How does the current in an infinite current sheet affect its surroundings?

The current in an infinite current sheet produces a magnetic field in its surroundings. This field can interact with other nearby magnetic fields, such as those produced by other currents or permanent magnets, and can also induce currents in nearby conductors.

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