# Worksheet: The Magnetic Force between Parallel Constant Currents

In this worksheet, we will practice calculating the magnetic force between two parallel current-carrying wires.

Q1:

Two long, straight wires are parallel and 10 cm apart. One carries a current of 2.0 A, the other a current of 5.0 A. What is the magnitude of the force per unit length between the wires?

• A N/m
• B N/m
• C N/m
• D N/m
• E N/m

Q2:

The two long parallel wires shown in the figure carry currents in the same direction. If and , where , what is the magnetic field at point ?

• A T
• B T
• C T
• D T
• E T

Q3:

The figure shows two long, straight, horizontal wires that are parallel and a distance apart, where . Both wires carry a current , but in opposite directions.

What is the magnitude of the magnetic field at ?

• A T
• B T
• C T
• D0.0 T
• E T

What is the magnitude of the magnetic field at

• A T
• B T
• C T
• D T
• E T

Q4:

Two long straight wires are parallel and 65 cm apart. If each wire carries a current of 80 A in the same direction, what is the magnetic force per unit length exerted on each wire?

• A N/m
• B N/m
• C N/m
• D N/m
• E N/m

Q5:

Two long parallel wires are hung by cords of length 4.00 cm, as shown in the figure. Each wire has a mass per unit length of 30.0 g/m and they carry the same current in opposite directions. What is the current if the cords are at a angle with respect to the vertical?