How to calculate the period in Lorentz force
Firstly, the electron is negatively charged. When the electron moves in the magnetic field, it will be affected by the Lorentz force perpendicular to the velocity direction:
fro = QVB... ①
under the action of Lorentz force, the electron moves in a uniform circular motion
F direction = fro... ②
and f direction = MV & #/ R... ③
simultaneous solution ①, ②, ③ the radius of electron motion r = MV / QB...... ④
v= ω R... ⑤
simultaneous ④ and ⑤ get:
1 ω= QB / M...... ⑥
so t = 2 π/ω= two π M / QB...... ⑦
because the magnetism of the magnet comes from the current, the current is the movement of the charge, so generally speaking, the magnetic field is generated by the change of the moving charge or electric field
from the point of view of modern physics, the ultimate components of charge in matter are only electrons (with unit negative charge) and protons (with unit positive charge), so negative charge is a point object with excess electrons, and positive charge is a point object with excess protons
extended data:
the relativity of the motion of the magnetic field is the same as that of the field source. The observer and his detection instrument can not measure the magnetic field proced by the moving field source, but can measure the magnetic field of the field source when the velocity is different from that of the field source
for example, in the reference system of the earth's surface, we determine that the electron at rest on the earth's surface does not proce a magnetic field, but the electron at rest on the earth's surface is constantly rotating with the earth's surface and around the sun
For another example, the current that causes the wire to generate an external magnetic field is the result of the directional movement of a large number of electrons. When the current carrying wire generates a magnetic field, each moving electron is not disturbed by the magnetic field of other electrons, because all electrons in the same row have the same magnetization and can not feel the existence of other electron magnetic fields∴T=2πm/qB
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根据圆周运[UNK]
mw² r=Bvq
m2π/T² r=Bwrq
T=2πm/Bq
The formula of Lorentz force: F = bqvsin θθ Is the angle between V and b)
according to the law of Lorentz force, Lorentz force can be expressed by equation, and the direction of Lorentz force can be judged by left-hand rule. Extend the left hand so that the thumb is perpendicular to the other four fingers and at the same level as the palm, so that the magnetic inction line enters from the palm, the four fingers point to the direction of positive charge movement, and the direction of the thumb is the direction of Lorentz force
Extended data:
ampere force is the macroscopic expression of Lorentz force, so the Lorentz force formula can be deced from the ampere force formula. Ampere force F = bil, current I = q / T
In the formula F = BL (Q / T) = QVB. From micro to macro, f = bil = bnqsvl = nbqv. F (ampere force) = NF (F is Lorentz force)QVB = MV ^ 2 / R
V = QBR / m linear velocity of circular motion
W = V / r = QB / M π/ w=2 π/ Qbm
should be corrected to t = 2 π/ w=2 π m/qB
t = 2 π/ω
pitch H = t * V
the round steel is finally processed into bolt, and the thread is spiral
charged particles with mass m and charged quantity Q (ignoring gravity) shoot into the uniform magnetic field with magnetic inction intensity B in the direction of velocity V perpendicular to the magnetic field, and Lorentz force provides centripetal force
QVB = MV ^ 2 / R orbital radius r = MV / QB
motion period T = 2 π r/v=2 π M / QB
the angle (deflection angle) between the velocity direction and the incident direction when a charged particle emits a magnetic field θ
by θ/ t=2 π/ T t= θ T/2 π=θ M / QB
note: θ The unit is in radian system