# On a straight wire that is in a uniform magnetic field with induction B = 0.5 T, an Ampere force F = 1.8 N

**On a straight wire that is in a uniform magnetic field with induction B = 0.5 T, an Ampere force F = 1.8 N acts with a current in it I = 0.9 A. Determine the length l of the active part of the wire if it is located at an angle a = 60 degrees to the vector.**

B = 0.5 T.

∠α = 60 °.

Famp = 1.8 N.

I = 0.9 A.

l -?

On a conductor with a current, in a magnetic field, the Ampere force Famp acts, the value of which is determined by the formula: Famp = I * B * l * sinα. Where I is the current in the conductor, B is the magnetic induction of the field, l is the length of the conductor, ∠α is the angle between the direction of the current and the vector of magnetic induction B.

The length of the active part of the conductor l is expressed by the formula: l = Famp / I * B * sinα.

l = 1.8 N / 0.9 A * 0.5 T * sinα60 ° = 4.6 m.

Answer: the active part of the conductor is l = 4.6 m.