The force on a current-carrying wire in a magnetic field can be calculated using the formula:
F = I * L * B * sin(theta)
Where:
F = force (in newtons)
I = current (in amperes)
L = length of the wire (in meters)
B = magnetic field strength (in teslas)
theta = angle between the wire and the magnetic field (90 degrees in this case)
Substitute the values given in the problem:
I = 4.0 A
L = 0.20 m
B = 0.40 T
theta = 90 degrees
F = 4.0 * 0.20 * 0.40 * sin(90)
F = 4.0 * 0.20 * 0.40 * 1
F = 0.32 N
Therefore, the force on the 0.20 m straight wire carrying 4.0 A of current in a magnetic field with a strength of 0.40 T when the wire is at right angles to the field is 0.32 N.
