# Worksheet: Magnetic Field due to a Long Straight Conductor Carrying a Constant Current

In this worksheet, we will practice calculating the magnitude of the magnetic field produced by a long straight current-carrying wire at a given distance from the wire.

Q1:

The magnitude of the magnetic field 50 cm from a long, thin, straight wire is 8.0 µT. What is the current through the wire?

Q2:

A long, straight, horizontal wire carries a left-to-right current of 20 A. If the wire is placed in a uniform magnetic field of magnitude T that is directed vertically downward, what is the resultant magnitude of the magnetic field 20 cm above the wire?

• A T
• B T
• C T
• D T
• E T

Q3:

A typical current in a lightning bolt is A. Estimate the magnetic field 5.0 m from the bolt.

• A T
• B T
• C T
• D T
• E T

Q4:

A transmission line strung 3.00 m above the ground carries a current of 335 A. What is the magnetic field on the ground directly below the wire?

• A T
• B T
• C T
• D T
• E T

Q5:

The figure shows two long straight horizontal wires that are parallel and a distance apart, where . If the wires carry currents and , in opposite directions, at what distance between them from the top wire is the net magnetic field zero?