(20 13? As shown in the figure, there is a uniform magnetic field perpendicular to the paper in the fourth quadrant of the plane rectangular coordinate system xoy, and the mass is m=5.0× 1.

The acceleration process of (1) charged particles is determined by

Kinetic energy theorem qu = 12mv2

Alternative data: v=20m/s

(2) Charged particles only do uniform circular motion under the Lorentz force,

Yes: qvB=mv2R

Get r = mvqb

Alternative data: r = 0.50m

And OPC OS 53 = 0.50m m.

So the center of the circle must be on the X axis, and the trajectory is as shown in the figure.

According to the geometric relationship, OQ = r+rsin53.

So OQ = 0.90 meters

(3) Charged particles are not emitted from the X axis (as shown in the figure),

From the geometric relationship: op > r'+r' cos 53 ①.

r′= mvqB′②

163t = 5.33t?

Answer: (1) The velocity V of charged particles when they reach point P is 20m/s;

(2) If the magnetic induction intensity B=2.0T and the particles leave the magnetic field from the Q point on the X axis, the distance of QO is 0.9m;;

(3) If the particles can't enter above the X-axis, the magnetic induction intensity b' satisfies the condition of more than 5.33T t. 。