Solve physics. Please analyze it in detail

The negative charge from point A to point B does deceleration motion, the electric field force hinders the movement, and does negative work, so the potential of point A is higher than point B, and the TV energy of point A is lower than point B, and the potential difference between the two points of AB can be found by the kinetic energy theorem, and the potential of point A can not be found, and the electric potential of point A is wrong and B is wrong and D is right, and it can be seen from Figure B that the acceleration of the charge motion is different, so the electric field is a non-uniform electric field and the electric field strength C pair cannot be found.

All I can say is that the misguided kid upstairs seems to be running for the answer. Isn't it a paradox that he analyzed that the potential energy of point A is higher than point B in A, but he analyzed that the potential energy of point B is higher than point A in B???

Here's what I think:

First of all, the diagram on the left shows that the negative charge decelerates from A to point B, indicating that the charge receives an electric field force from B to A, and since the charge is negatively charged, it can be concluded that the potential energy of A is higher than that of point B. The problem gives that the charge only moves under the action of the electric field force, and from the conservation of energy, it can be seen that the magnitude of the work done by the electric field force from a to b is equal to the kinetic energy of the charge at point A (WAB = MV square 2).

Analyzing the diagram on the right, from this diagram we can see that the charge is decelerating, and the acceleration is changing, so we can infer that the electric field is a non-uniform electric field, but from this diagram we can calculate the acceleration a of the charge at any time (that is, the tangent of the corresponding curve at that time point); and a=f m=eq m, so the electric field strength can be calculated, but the calculated electric field strength also changes with time.

Let's take a look at the options again, a, the first half of the sentence is correct (the analysis process has been given above), the second half of the sentence is wrong, the reason will be given in the D option.

b, the option is correct, the solution process has been given in the above analysis of the left diagram.

c, false, the algorithm for the electric field strength is given in the above analysis of the figure on the right.

d, the first half of the sentence is correct; For the second half of the sentence, because the electric field strength is varied, the potential difference between a and b may also be constantly changing and cannot be found (of course, it may not be the non-uniform electric field caused by the change of the potential difference between a and b, so if this topic is a multiple-choice question, this option can also be considered correct); Only the average potential difference between a and b during this movement can be calculated. For this reason, and the potential energy at point B is also unknown, the potential energy at point A cannot be found.

To sum up, choose B; Of course, this only represents my personal point of view, and you can put forward different opinions and we will work together.

The correct answer should be D.

The first equation e=u d, is a relation in a uniform electric field, u is the voltage between two points, d is the distance between the two points along the direction of the electric field, and e is the strength of the electric field in pure denier degrees. In this problem, u is the voltage between the two plates, and d is the distance between the two plates (since the electric field is perpendicular to the plate, the distance d between the two plates is the distance along the direction of the electric field).

The second equation is Newton's second law. The particle is experiencing the electric field force qe in the electric field, according to Newton's second law (f=ma), there is: qe=ma, so there is a=qe m.

The third equation is the law of uniform acceleration of linear motion. A uniform acceleration linear motion with an initial velocity of 0 has the following rule: v square = 2as = 2ad (the title says:

The particle moves from one allegro to another, so the displacement s of the particle s is equal to the distance d between the two plates), and the two sides are squared to obtain: v = 2ad under the root number.

Substituting the first equation into the second equation, substituting the obtained result into the third equation, and substituting the first result into the expression of kinetic energy to get the conclusion.

First of all, the n=1 is called the ground state, the n>1 is called the excited state, and the n is called the ionization state. where n=2 is called the first excited state, n=3 is called the second excited state, and n=4 is called the third excited state.......

Analysis: Option a: The energy of the first excited state of the helium ion, that is, by substituting n=2 into the calculation, it is easy to see that this option is correct.

Option b: Helium ions transition from the first excited state to the ground state, the energy of the radiated photon is E light = E2 - E1 (corresponding to n = 2 and n = 1 substitution respectively), calculate the photon frequency V according to E light = Hv (h is Planck's constant), and then get the momentum of the photon from P = Hv C (C is the speed of light in a vacuum), note that each unit of quantity is calculated in Si units to know whether this option is wrong (I didn't calculate, you calculate it yourself).

Option c: The energy of the helium ion transitioning from the first excited state to the ground state emitting photons is equal to 3 times the ionization energy of the hydrogen atom, then when the hydrogen atom in the ground state is irradiated with it, the kinetic energy of the escaping electron is equal to 2 times the ionization energy of the hydrogen atom, that is, the kinetic energy is 2*. This option is correct.

Option d: The photon energy radiated by the helium ion from the second excited state (n=3) to the ground state is equal to 4* ev=, and the maximum initial kinetic energy of the photoelectron is irradiated with sodium metal. The option is incorrect.

a=f m, take the vertical upward direction as the positive direction, where f is the resultant force of the wooden box, let the support force be n, and the gravity force is g, that is, there is f n-g; Then:

a) The elevator accelerates and rises with the acceleration of a; , b) the elevator rises with a uniform acceleration of a; -2=(n-g) m, note that the direction of acceleration here is downward, and "uniform deceleration" means that the direction of acceleration is opposite to the direction of motion;

c) The elevator decelerates and descends with an acceleration of a; , note that the direction of acceleration here is upward, and "uniform deceleration" means that the direction of acceleration is opposite to the direction of motion;

d) The elevator rises at a constant speed of V 3m s; 0＝(n-g)/m；Here the acceleration is 0;

According to the above four equations, it can be seen that under the same condition that g and m are the same, n in c is the largest; This is the support force received by the wooden box, and according to the action and reaction force, in this case, the pressure on the floor is also the greatest.

So the exact answer is (c).

According to the law of conservation of energy, there is, at the lowest point.

1/2mv^2 = mgl - q → v = ( 2(gl-q/m))^1/2)

i = blv/r

f = bli = b^2l^2 ( 2(gl-q/m))^1/2) / r

Their kinetic energy increment is equal to the work done by the electric field force.

ek=qu=q*q/c

The ratio of their kinetic energy increments is ek1 ek2 2 :1

Upstairs is the right solution.

Seek only the truth, not adoption.

The driver's normal reaction time = normal thinking distance Speed =;

Reaction time after drinking = Thinking distance after drinking Speed = 12m 15m s = i.e., reaction time after drinking is more than normal;

vt=v0+at，0=20+at。。。s=v0t+1/2at²，50-10=20t+1/2at²。。

Syntagion, the solution is t=4s, a=-5m s.

When V0=25M S, the normal braking distance is S=75M, and the drunken braking distance S1=S+(, so when you find that there is a dangerous situation in front of 80M, you cannot stop safely after drinking.

The tip of the needle is the negative electrode, which emits an electron beam, and the electrons combine with the soot particles, and the soot is negatively charged and moves towards the positive aluminum plate. Therefore, A is wrong, B is wrong, C is correct, and the electric field at the tip of the needle is strongest close to the aluminum plate and gradually weakens D error.

Air molecules in a strong electric field will be ionized into electrons and positive ions, so the smoke and dust are "blown" through I don't see the diagram We have to know how smoke moves, because the electrons are too small, the smoke moves with positive ions, and there is always a force in the electric field, so b is true and c is false, would you draw a map of the electric field? According to the diagram, the closer you get to the aluminum plate, the more sparse the electric field lines are. d is false.