In a uniform magnetic field with an induction of 1 T, a wire l = 50 cm is placed on two supports.

In a uniform magnetic field with an induction of 1 T, a wire l = 50 cm is placed on two supports. At what value of current will the conductor be separated from the supports, if the mass of the conductor is 1 kg, and the induction vector B and the conductor with current are mutually perpendicular.

B = 1 T.

l = 50 cm = 0.5 m.

m = 1 kg.

g = 9.8 m / s2.

∠α = 90 °.

I -?

The separation from the supports will occur when the force directed vertically upward is slightly greater than the force directed vertically downward.

A conductor with a current in a magnetic field is acted upon vertically up by the Ampere force Famp, and vertically down by the force of gravity Fт.

Fump = Ft.

Ampere force is determined by the formula: Famp = I * B * l * sinα.

The force of gravity is determined by the formula: Ft = m * g.

I * B * l * sinα = m * g.

I = m * g / B * l * sinα.

I = 1 kg * 9.8 m / s2 / 1 T * 0.5 m * sin90 ° = 19.6 A.

Answer: with a current strength I> 19.6 A, the conductor will separate from the supports.