In a uniform magnetic field, a wire 1.5 m long moves at a speed of 4 m / s perpendicular to the lines of magnetic induction.In this case, an EMF of induction of 0.3 V appears in it, determine the modulus of the magnetic field induction vector
V = 4 m / s.
L = 1.5 m.
∠α = 90 °.
EMF = 0.3 V.
Since when the conductor moves, there is a change in the magnetic flux Ф, then according to Faraday’s law of electromagnetic induction, an induction current arises in it.
The EMF of induction is directly proportional to the rate of change in the magnetic flux: EMF = ΔF / t, where t is the time of change in the magnetic flux.
ΔF = Δ (B * S * cos (90 ° – α)).
Since the magnetic induction of the field does not change, then ΔF = B * ΔS * cos0 °, where ΔS is the area that the conductor describes when moving.
ΔS = L * d, where d is the distance the conductor moved forward.
The d / t ratio is called the speed of the conductor V: V = d / t.
EMF = B * L * d * / t = B * L * V.
B = EMF / L * V.
B = 0.3 V / 1.5 m * 4 m / s = 0.05 T.
Answer: the magnetic induction of the field in which the conductor moves is B = 0.05 T.