(1) In the magnetic field, the charge moves in a uniform circular motion, so qv0B=m(v0)^2/rr=mv0/qB
It is easy to know from geometric knowledge that the center of the circle is located at x On the negative half-axis of the axis,
Therefore the position coordinate A (-mv0/qB, -mv0/qB) of the charged particle crossing the magnetic field boundary for the first time
(2)
The calculation of this question is not difficult, the key lies in the analysis of the process of motion:
O-->A charge performing circular motion in a magnetic field is the first problem to solve;
A-->B?+?B--> Is this the first time? the charge moves in the electric field. It is a movement process with an initial velocity of v0 and an acceleration of -Eq/m. Finally, the load returns to point A. The speed remains unchanged and the direction changes to B-->. HAS ? The total time is t2=2v0/a=2mv0/qE;
Step A-->C is:the charge makes a circular motion in the magnetic field for the second time, speed v0;
OA+AC is exactly the time required for the charge v0 to perform a circular movement, so t1=T=2πm/qB
Suppose that the stage C-->D either the charge The second movement in the electric field is a quasi-launch movement with an initial speed v0 (in the positive direction of the y axis) and an acceleration a=Eq/m (in the positive direction of the y axis x). with OM when Sx?=Sy? At point D: v0t=1/2at^2
Can we obtain t=2mv0/Eq? Then Sx?=?Sy?=v0t?=?2m(v0 )^2?/?Eq?
Analysis: Sx?=?Sy?=v0t?=?2m(v0)^2?/?Eq and ?2r?=?2mv0/qBIWe know that v0>E╱B
So Sx?=?Sy?>?2r?So point D should be located in the first quadrant, the hypothesis is not true
So the load movement the trajectory is C -->E time of movement t3=2r/v0= 2m/qB
Therefore, the time it takes for charged particles to move away from the origin ofs coordinates and finally leave the electric and magnetic circuits the field zones are t=t1+t2+t3
That is to say t=2(π+1) m/qB+2mv0/ qE ?
(1)Electromotive force 21V< /p>
(2)Ur:U lamp=r:R lamp? That is to say (21V-0.3A×60Ω): (0.3A×60Ω)=r: 60Ωr=10Ω
( 3)P=U lamp×I lamp=5.4W
How to translate salt lakes
The formation of salt lakes requires certain natural conditions, the most important of which are the following two points: climate arid or semi-arid.
Development information:
Salt lake is a type of saltwater lake, with high salinity in arid areas .Very high lake. Freshwater lakes have salinity less than 1 g/L, saltwater lakes have salinity greater than 1 g/L, and salt lakes have salinity greater than 35 g/L. The salt lake is the product of the lake's development into old age. It is rich in a variety of salts and is asignificant mineral resource.
A salt lake is a body of salty water, generally referring to a lake with a salinity w(NaCleq)>3.5% (higher than the average salinity of seawater). It also includes lakes where surface brine has dried). and is composed of salt sediments and dry salt lake (underground brine lake) composed of intercrystalline brine.
There are about 200 types of salt minerals deposited in the salt lake. Humans have extracted large quantities of rock salt, alkali, Glauber's salt, and potassium, lithium, magnesium, boron, bromine, saltpeter, gypsum, and medical sludge from salt lakes for basic chemical industry, agriculture, light industry, metallurgy, construction and medical treatment. other important raw materials.
The salt lake also contains industrially important resources such as rubidium, cesium, tungsten, strontium, uranium, calcium chloride, magnesite, zeolite and hectorite.
The salt lake also contains a large number of special biological resources such as halophilic algae, Artemia halozoa, spirulina and rotifers, as well as drought tolerant and saline-alkali tolerance genetic resources, which have a significant economic impact. scientific value and significance.
They provide humans with simple substances, natural food pigments, energy, a variety of industrial scientific materials, and purify the environment, opening up good prospects for transforming lakes salted areas in “fertile agricultural land”. At the same time, the salt lake serves as an important tourism resource and medical silt resource. The heat storage characteristics of salt lake brine began to be used in "salt water solar pools" to generate electricity.
Salt lakes means salt lake.
Salt lake is a type of saltwater lake, a lake with high salinity in arid areas. Freshwater lakes have salinity less than 1 g/L, saltwater lakes have salinity greater than 1 g/L, and salt lakes have salinity greater than 35 g/L. The salt lake is the product of the lake's development into old age. It is rich in a variety of salts and is an important mineral resource.
A salt lake is a body of salty water, generally referring to a lake with a salinity w(NaCleq)>3.5% (higher than the average salinity of seawater). It also includes lakes where surface brine has dried). and is composed of salt sediments and dry salt lake (underground brine lake) composed of intercrystalline brine. There are about 200 types of salt minerals deposited in the salt lake.
Humans have mined large quantities of rock salt, alkali, mirabiliteand potassium, lithium, magnesium, boron, bromine, saltpeter, gypsum and medical sludge from salt lakes for the basic chemical industry, agriculture, light industry, metallurgy, construction and medicine and other important raw materials.
The salt lake also contains industrially important resources such as rubidium, cesium, tungsten, strontium, uranium, calcium chloride, magnesite, zeolite and hectorite. The salt lake also develops a large number of special biological resources such as halophilic algae, Artemia halozoa, spirulina, rotifers and drought and salt-alkali tolerant genetic resources, having economic value and scientific importance important. They get eggs and natural food pigments. humans, energy, various industrial scientific materials and a purified environment, opening up good prospects for trtransform the salt lake into “fertile agricultural land”.
At the same time, the Salt Lake is an important tourism resource and medical mud resources. The heat storage characteristics of salt lake brine began to be used in "salt water solar pools" to generate electricity.