How Does a Magnetic Field Affect a Wire Carrying Current?

[Physics345]

Homework Statement

A magnetic field of 1.4 T [N] is 4.0 m wide. A very long wire crosses the field.

a) If the current in the wire is 2.0 A [W], find the magnetic force on the wire.

b) What will happen to the force on the wire if
i) The wire is rotated slightly in the horizontal plane?
ii) The current is doubled?
iii) The magnetic field is reversed?

Homework Equations

F_m=ILB

The Attempt at a Solution

a)

a) F_m=ILB
F_m=(-2.0)(4.0)(1.4) F_m=-11.2N=11N
F_m=11N [down]
Therefore the magnetic force on the wire is 11N [down]

b)

i) Since the wire is no longer in a 90 degree angle the magnetic force will decrease and the angle will change

ii) The magnetic force will double and the current will move twice as fast.

iii) The direction of the force will reverse.

 

[Gene Naden]

Hi there,
I think you are OK with a and b, but not c. The magnetic field is not what is producing the current. The current is produced by a battery, or something, outside of the magnetic field.

Thanks,
Gene

 

[Physics345]

Hi there,
I think you are OK with a and b, but not c. The magnetic field is not what is producing the current. The current is produced by a battery, or something, outside of the magnetic field.

Thanks,
Gene

What are you referring to when you say c?
If you are referring to 2. iii), then good call I just noticed that is wrong it should be: The direction of the magnetic force will reverse