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This statement is only half true. First of all, because the electric charge is moving, it does look like two electric currents to an outsider. However, since your train is already moving at a speed close to the speed of light, consider the effects of relativity.

At this point, the electromagnetic field is described by a four-dimensional tensor in a Minkowski space, and the usual electromagnetic theory has failed. If the magnetic field is analyzed separately, there is still a certain comparability with the magnetic field generated by the two currents, because the magnetic field lines are circular, but the value of the magnetic induction intensity is different from the usual calculation results, but the effect is indeed two charges attracted. However, at this time, it is also necessary to consider the change of the electric field after the movement of the two charges, because the electric field strength in the direction of the two charge lines becomes very large, so the repulsion of the electric field force is stronger, and the overall effect is that the two charges are still repulsive, and there is no violation of the basic law of charge.

By the way: if the train is moving at the speed of light, then the electric and magnetic forces between the two charges are exactly canceled out, that is, the charges do not attract or repel, however, a train that reaches the speed of light cannot do this.

There is no relative motion of two electrons, where does the relative current come from.

Roentgenium, Lorenz, Becquerel, Pierre Curie, Galileo, etc.

1. Roentgenium. Wilhelm Konrad Röntgen (27 March 1845 – 10 February 1923) was a German physicist.

The discovery of X-rays on November 8, 1895, paved the way for the pioneering of medical imaging technology, and he was awarded the first Nobel Prize in Physics in 1901.

2. Lorenz.

Hendrik Antoon Lorentz (1853-1928) was a Dutch physicist, mathematician, and founder of the theory of electrons. In 1902, he was awarded the Nobel Prize in Physics with Peter Zeeman.

3. Galileo.

Galileo Galilei (15 February 1564 – 8 January 1642) was an Italian physicist, mathematician, astronomer and philosopher, and an important figure in the Scientific Revolution. His achievements included improvements to telescopes and the astronomical observations they bringed, as well as support for Copernicus' heliocentric theory.

4. Becquerel.

Antoine Henri Becquerel (1852-1908), French physicist. Born in France in 1852.

For the discovery of natural radioactivity, he and Pierre Curie (1859-1906) and Marie Curie (1867-1934) were recognized for their in-depth research and outstanding contributions to radiology.

5. Pierre Curie.

Pierre Curie (15 May 1859 – 19 April 1906), a native of Paris, was a famous French physicist and husband of Marie Curie. too"Curie's Law"The discoverer of . In 1903, he was awarded the Nobel Prize in Physics with Marie Curie and Becquerel.

If a is selected and the specific heat is q, then there is w = qmt temperature difference = time.

Q=p(t2 t1) 2m (t2 t1) and p(t4 t1) 2m (t3 t1) are compared, because t2 t1 t1 t1 is greater than t3 t1 t4 t1 (see slope).

Therefore, if q is less than p(t4 t1) 2m(t temperature 3 t temperature 1), the calculation formula of abc is larger.

It can also be thought of as a period of time between t1 and t4, although it is endothermic, but the energy that is converted into a three-state change is not reflected in the temperature, and this p work time should be reduced, which is smaller than p(t4 t1) 2m (t temperature 3 t temperature 1), which is p(t4-t3+t2 t1) 2m (t temperature 3 t temperature 1).

b The calculation of the specific heat capacity does not take into account the three-phase morphological change of the substance and is equal to the slope of the oblique line in the figure.

The principle of independent action of force: each force has an effect on the object, producing acceleration, and the actual acceleration of the object depends on the net force experienced by the object.

The force is a vector quantity, and the magnitude is calculated using the parallelogram rule, which cannot be directly added or subtracted, unless the force is in a straight line.

First, the two forces are synthesized using the parallelogram rule to find the resultant force (the Pythagorean theorem is used to find the magnitude perpendicular to each other, and the angle is expressed by trigonometric functions to determine the direction), and then Newton's second law is used to find the acceleration when acting at the same time.

The answer to this question C is correct.

It's obviously c... Draw a picture. The size is a1 square + a2 square under the root number. The direction is what C says. 5 seconds to complete the problem...

The optical path difference of the reflected light on the upper and lower surfaces of the air-split film is:

2nd+2 (n=1 is the refractive index of the air, d is the thickness of the air film at the reflection).

The conditions for interference to cancel out to form dark fringes are:

2nd+λ/2=(2k+1)λ/2 (k=0,1,2.。。The difference between the thickness of the air film corresponding to the two adjacent dark fringes d is:

d=d2-d1=λ/2n

The spacing x of two adjacent dark stripes is:

x=△d/sinθ=λ/2nsinθ

For the apex angle of the split tip, due to the small size, the diameter of the sin tan filament is the distance from the filament to the edge.

x=589×10^-9m×=