# A conductor with a length of 30 cm is located horizontally. What value should the magnetic field induction

**A conductor with a length of 30 cm is located horizontally. What value should the magnetic field induction have so that the gravity force of a conductor with a mass of 6 g is balanced by the Ampere force? A current of 5A flows through the conductor (take g = 10m / sq.s)?**

L = 30cm = 0.3m.

m = 6 g = 0.006 kg.

g = 10 m / s2.

I = 5 A.

V – ?

According to 1 Newton’s law, the condition for the presence of a conductor at rest is the balancing of the forces that act on it.

The force of gravity Ft is balanced by the force of Ampere Famp: Ft = Famp.

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

Ampere force Famp is determined by the formula: Famp = I * B * L

m * g = I * B * L.

B = m * g / I * L.

B = 0.006 kg * 10 m / s2 / 5 A * 0.3 m = 0.04 T.

Answer: the magnetic induction of the field is B = 0.04 T.