# Ampère's Law

## Practice

### practice problem 1

Use the Biot-Savart law to determine the magnetic field strength…

- a distance
*r*away from an infinitely long current carrying wire - a distance
*x*away from a loop of current with radius*a*(on the axis of the loop). - anywhere inside a solenoid with
*n*turns per unit length

#### solution

These problems were solved in the discussion page of this topic. Here are the results once more without any detail.

### practice problem 2

Use Ampére's law to determine the magnetic field strength…

- a distance
*r*away from an infinitely long current carrying wire - anywhere on either side of an infinite, flat sheet with a surface current density σ
- inside a solenoid with
*n*turns per unit length - inside a toroid (a toroidal solenoid) with a total of
*N*turns - inside a wire of radius
*R*at any distance*r*from its axis

#### solution

These problems were solved in the discussion page of this section. No need to write them out in full again. Here's a summary of the results.

- a distance
*r*away from an infinitely long current carrying wire[straight wire with amperean path goes here]

*B*=μ _{0}*I*2π *r* - anywhere on either side of an infinite, flat sheet with a surface current density σ
[infinite sheet with amperean path goes here]

*B*=μ _{0}σ2 - anywhere inside a solenoid with
*n*turns per unit length[solenoid with amperean path goes here]

*B*= μ_{0}*nI* - anywhere inside a toroid (a toroidal solenoid) with a total of
*N*turns[toroid with amperean path goes here]

*B*=μ _{0}*NI*2π *r* - inside a wire of radius
*R*at any distance*r*from its axis[amperean path inside a wire goes here]

Inside a wire with total current

*I*.*B*=μ _{0}*Ir*2π *R*^{2}Inside a wire with uniform current density ρ.

*B*=μ _{0}ρ*r*2

### practice problem 3

Write something.

#### solution

Answer it.

### practice problem 4

Write something completely different.

#### solution

Answer it.