Lorraine Said:

Need a topic for a modern physics experiment?

We Answered:

http://arxiv.org/abs/0810.3933

Leslie Said:

help on a question in modern physics......?

We Answered:

Here the answer will require you to use Special Relativity to calculate the time dilation due to the speed of the muon traveling at 0.99c. Of course in effect increases the half life of the muon, thus the number of muons reaching the ground will be more than if there were no time dilation.

t' = t / sqrt(1-(v/c)²) = 10.63 micro-seconds

Darryl Said:

Modern Physics: PLS HELP!! (short) Find width of slit in single slit diffraction experiment given...?

We Answered:

You are on the right track

d*sin(θ) = mλ

λ comes from the de Broglie wave length of the electron


So λ = h/me*v where me is the mass of the electron

So d = mh/(me*v*sin(θ)) = 2*6.63x10^-34/(9.11x10^-31*100*sin(5))) = 1.67x10^-4m

Norman Said:

Does anyone know what type of experiment this picture is showing?

We Answered:

It's of a particle-pair creation (note the two spirals in the upper-right and lower right of the picture, and how they pop "out of nowhere"). The original ray or particle was likely uncharged, since the particles spiral in different senses within the magnetic field (applied perpendicular to the plane of the picture), indicating opposite charges and roughly equal masses. This picture was likely taken in a bubble chamber ( http://en.wikipedia.org/wiki/Bubble_cham… ).

Probably the answer being sought is one or more of:
1) Particle-pair creation;
2) Bubble chamber;
3) Cloud chamber.

Kathy Said:

Does modern theoretical physics have room for spirituality and the "supernatural"?

We Answered:

At this point I think that modern physicists do not have enough evidence of such things to prove or discount them. We know that we broadcast signals from our brain (alpha, beta, and theta waves). but as of yet we do not know for sure what these signals are capable of or if other humans are able to receive and decipher them.

To be totally objective, much of what could have been considered to be supernatural 100 years ago, is now scientifically provable and can be considered very natural. So it is impossible to say that what is supernatural today could not be considered natural as science progresses and we gain a better understanding of the true nature of the existence of our universe.
This does not mean that you can call what is supernatural today a fact based on the possibility of scientific recognition in the future. It simply means that "fact" is relative to the current capacity of understanding nature.
I do believe there is room for such things in physics, even a thirst. And I can't wait until the next big breakthrough. I love the Idea of having more capabilities than we are aware of, being able to manipulate things without physical contact, or communicate through thought, etc.. The possibilities are fascinating.

Great question

Marlene Said:

Waves and Modern Physics - Work function of aluminum ?

We Answered:

Photoelectron energy = photon energy = work function + stopping voltage
Photon energy = hc/lambda = 4.592 eV
Work function = photon energy - stopping voltage = 4.186 eV