Add 50 more questions about atomic physics afterwards!! Urgent!!!!

Bi undergoes decay, and the mass of the released electrons is negligible with respect to the atomic mass.

14si15p——>30 14si+e+

8.Neutrons protons.

9.Proton Neutron Proton Number of Protons plus Number of Neutrons Proton Neutron.

7n 13 6c α+10 5b——>1 0n+13 7n 13 7n——>13 6c+e+

14.Particle scattering experiment Particle bombardment of nitrogen nuclei Particles bombardment of beryllium nuclei.

18.Because the decay rate of sodium before entering the human body is 2000 seconds, the half-life is 15 hours, after 30 hours, the total amount of sodium is reduced to 1 4, and the decay rate of sodium also becomes 1 4, that is, 500 seconds, and 1cm3 is 5 min, so the total amount of blood is 1cm3 * 500 seconds 5 min=1cm3*100*60=6l

19.Let the electron mass be m0, and the k e r 2 = m0*v 2 r gives v = root number (ke 2 m0r), the angular velocity is w = v r = root number (ke 2 m0r 3), the frequency is f = w 2 = root number (ke 2 m0r 3) 2, and the kinetic energy is ek = 1 2*m0*v 2= ke 2 2r

20.From the decay formula 1 8 = (1 2) (t 5568), the solution is t = 16704, that is, about 17,000 years.

22.(1) 4 2 He ( ) 2) E- (3) (Ray) (4) E + (5) 19 9F (6) 3 1H (7) 1 0N (8) 43 20Ca

The first question shouldn't be right, but I forgot the specific situation of the scattering experiment, but it shouldn't be right from your options, first of all, it is impossible for the positive charge to be evenly distributed in the atoms, the second question: choose A, the third question doesn't seem to be right, A decays once and can decay a proton? The difference between the proton electrons of the two should be divided by the number of proton electrons to be released for each decay, and it is concluded that there have been several decays of a and a few decays of b, and B should be selected for the fourth question

Question 5: 10g Question 6: p29 p30-e=p29, the second null in question 9 should be a proton. I can only give you so much, these questions don't feel like I'm very good at the test.

Set the resistance of the electric car to dismantle the empty brigade of the brigade of the brigade bench is f, and the tram is only subject to resistance after turning off the motor, and the direction of movement of the tram is in the positive direction, and the definition of acceleration, the resistance acceleration of the tram is.

a=(0-15)/10=

The mass of the tram is 4*10 3kg

The resistance of the tram is f=ma=4*10 3kg*

Density: (p alcohol = cubic centimeters).

Mass = P alcohol * V = cubic centimeter * 500ml = 400g

"45" means that 100ml of liquor contains 45ml of alcohol and 55ml of water, so the quality of this 100ml of liquor is the sum of the two.

The volume of alcohol * the density of alcohol + the volume of water * the density of water and the mass of water divided by the volume (one hundred milliliters) can get the density of the liquor, the density of the liquor multiplied by the volume of the liquor five hundred milliliters can get the mass of the liquor, and the calculation part will be processed by itself.

According to the conditions, the volume of alcohol in the whole bottle of liquor v1 = 500ml 45% = 225ml, and the volume of water v2 = 500ml-225ml = 275ml

We know the density of water p water = grams of cubic centimeters, and we tell p alcohol = cubic centimeters in the title, we can find the quality of water in the wine and the quality of the alcohol, and the sum of the two is the quality of the bottle. With the formula (m=pv).

Find out the quality, and then use the mass 500ml is the density of the reminder, do this kind of problem to pay attention to the unit.

vWater = 500*

v alcohol = 500-275 = 225ml

Mass m = v water * 1 + v alcohol * = 455g density p = m v = 455 500 = cubic centimeters.

(1) The velocity of point b: v = 5m s

f = direction straight downward;

2) wf =

Process: 2r=, t=

v*t=2m,v=2/

f+mg=v2m/r,f=

From the kinetic energy of the object at point B, the kinetic energy at point A is found to be 1 2*MV12, then FS-FS=1 2*MV12, and FS=—

Answer a c d

For two inverting wave sources to interfere, if the difference between the distance between a certain point and the two wave sources is equal to an even multiple of half a wavelength, then the point is the point of vibration attenuation.

According to the title, the direction of motion of the two wave sources is always opposite during the vibration, so the phase is opposite. The amplitude of point p is 0, that is, point p is the point at which the vibration is weakened, so the difference between the distance between p and the two wave sources is equal to an even multiple of half a wavelength.

Choose B, this is the same as the dark fringe of light interference, if the distance between the two coherent wave sources and the same point is half an odd multiple of wavelength, then the dark fringe will appear superimposed at this point; The dark streak indicates the weakening of the energy, which is manifested in the displacement of the fixed point, that is, the displacement caused by the two vibrations is equal in magnitude and opposite in the opposite direction, and the sum is always equal to zero, and there is no displacement. Therefore, if you choose B, the ACD options are actually the same, and they are all even multiples of half wavelengths.

If the vibration direction of the two columns of waves is always opposite, then the condition for them to appear vibration strengthening point is an odd multiple of the wave range difference of half a wavelength, and the condition for the occurrence of a vibration weakening point is an even multiple of the wave range difference of half a wavelength, that is, 1 wavelength, 2 wavelengths, etc., so ACD is correct, if the vibration direction of the two columns of waves is always the same, then the condition for them to appear vibration strengthening point is an even multiple of the wave range difference of half a wavelength, and the condition for the occurrence of a vibration weakening point is an odd multiple of the wave range difference of half a wavelength.

Landlord, lack of conditions, right? What is the mass number of pb? Which isotope is it? Calculated, this atomic mass is:

Generally, this kind of problem will be accurate to 4 or 5 decimal places, and 1u= mass and energy under natural units are not distinguished.

I guess this should be done according to the conservation of mass and energy. The combination of 6 neutrons and 6 protons into a carbon nucleus can be seen as first combining into 3 A particles, which are released, and then 3 A particles combining into a carbon nucleus, released, and the total energy is added.