Recent content by Mark Zhu

I am confused about the disintegration energies of beta minus and beta plus decay. Regarding beta minus decay, the textbook says that "the number of electron masses has been accounted for in Equation (12.38)." What does that mean? Usually the disintegration energy is simply the mass of the...

Yes. The semi-empirical liquid drop model. Thank you for your help. I understand it now. I confused change in energy with binding energy.

If we are talking in terms of mass in mass-energy, then that makes sense. Because later there is another equation later introduced in the attachment below, and in that equation, the last term delta is positive for even-even nuclei and negative for odd-odd nuclei. As even-even nuclei are more...

This is an example from my textbook that I am having trouble understanding. So the binding energy of Beryllium-8 is positive 56.6 MeV, so it means the nuclide is stable, right? My textbook seems to use the reference of positive binding energy as being stable. And so that means alpha decay for...

Thank you, I also consulted with someone else and we thought the textbook had made an error as well.

This is a problem about converting from the phasor to time domain. I am having trouble following the math that the textbook is doing. I was thinking the final answer should be: i(d, t) = 0.20 cos(ωt + βd + 159◦) - 0.091 cos(ωt − βd + 185.6◦) emphasize the minus 0.091 instead of plus 0.091 as...

Actually, it does later say, "In its rest frame, the source emits n waves of frequency f0 during the proper time T0'. n = f0T0'."

I understand now, thanks. Btw, I meant when the textbook calculates the frequency of the wave in frame K, it uses Lorentz transformations.

3.3 x 10^-8 s. When it comes to time, however, the textbook relates the proper time to the time as seen by the astronomer in frame K.

Ok, that is confusing because I was told to use Lorentz Transformation when dealing with speeds near the speed of light, and in this case the light is traveling at speed c.

1) It is the length of the wave as seen by the astronomer. 2) v/(1-v^2/c^2) 3) v/(1-v^2/c^2) 4) Because the frame K' is moving at a constant velocity with respect to frame K at an unknown velocity v, we want to use relativity. So you're saying we don't need to view it in relativistic terms? I...

I am confused about how to find the length of a wave train emitted within a time interval T and that is moving with speed c relative to a moving frame that is itself moving with velocity v. Apparently the answer is that the wave train's length is cT - vT, but I tried to plug in variables into...

Thank you for your help

What do you mean same order of magnitude? Isn't n the index of refraction?

I am wondering if there is a typo in my textbook. Please see the attachment. The textbook says "...keeping only the lowest term in x = v/c." I am wondering if it should be "x = v/(nc)," as I circled in blue on the left side. It is a binomial expansion of the denominator. Shouldn't x be v/(nc)...