Threshold Definition and 120 Threads

Understanding the amount of 'power' in Watts to kill a human. It is said that around 20ma is enough to kill. So I would have thought it does not matter about the voltage as long as 20ma is passing through the heart. obviously it would require different voltages depending of the resistance...

[SOLVED] sound intensity - the threshold of pain Homework Statement You are investigating the report of a UFO landing in an isolated portion of New Mexico, and encounter a strange object that is radiating sound waves uniformly in all directions. Assume that the sound comes from a point...

Homework Statement The photoelectric threshold wavelength of a tungsten surface is 272nm A) what is the threshold frequency of this tungsten b) what is the work function in electonVolts of this tungsten C) Calculate the maximum kinetic energy in eV of the electrons ejected from this...

Is it possible to have a negative sound intensity level? A sound that is below the threshold of human hearing has... (A) a negative intensity level (in dB). (B) a negative intensity (in W/m^2 ). (C) an intensity level of zero. (D)an intensity level less than 1 dB , but greater than 0...

Homework Statement Light of intensity 1.5 x 10 (x)-2 Wm/2 and wavelength 250 x 10 (x)-9m is incident on an iron surface of area 1 x 10 (x) -4 m2. The iron surface reflects 95% of the light. The threshold frequency for iron is 1.1 x 10x15 Hz. Calculate: 1) The intensity of light available for...

This has been annoying me since I read this somewhere. Beta decay is only possible if energetically allowed. For electron emission this means: [M(A,Z) - M(A,Z+1)]c^2 >0 For positron emission this is [M(A,Z) - M(A,Z-1) - 2m_e]c^2 >0 Why the asymmetry? I would naively think that...

I have two questions related to statistical physics or particle physics, could somebody help ?If this is not the right place for these questions, please advise. 1 What does 'percolation threshold' means for a system of particles? 2 What is "periodic boundary" in a particulate system? Is it...

There are only so many neurons and so much "firing intensity" that neurons can fire. So the question is - is there a possible maximum threshold of pain or heat? This reminds me of Weber's Law. But Weber's Law still would predict no maximum intensity of perception - but logically there should be one.

Homework Statement This is a pretty simple problem... Yet I got the wrong answer.. Hmm... "Find the threshold frequency for a calcium surface whose work function is 3.33eV" W=3.33eV = 3.33eV * 1.6x10^-19 J = 5.33x10^19 J f = ? h=6.63x10^-34 J*S Homework Equations f=W/h The Attempt at a...

With what speed will the fastest photoelectrons be emitted from a surface wih threshold wavelength of 600nm when the surface is illuminated with light of wavelength of 400nm?

the pain threshold of your ears is about 130 phon.The sound levelclose to a jet (r=1m) when it takes off is about 150 phon.How far do you have to go away in order to lower the intensity level below the pain threshold?? anyone pls tell me the formula to use so that i can calculate as i can't...

the question is: in a photoelectric effect, it is found that incident photons with energy 5.00 eV will produce electrons with a maximum kinetic energy 3.00 eV. What is the threshold frequency of this material? the equation i have to work with is KE=hf-hf(sub t) and here the way to figure...

Is is possible to shape and configure a nuclear charge to produce only a 700 tonne detonation? (0.7 kilotons, 0.7 kt) What is the current minimum threshold yield for a nuclear charge detonation based upon current nuclear technology? [/Color] Reference...

1) what is a decibel? What is the threhold for pain in decibels? 2) what is a standing wave? 3) what produces sound waves? 4) Explain how the human ear receives sound and transmits it to the brain THANKS,

I can understand why the threshold for pair priduction is 2m0c^2. But why is the threshold for triplet production 4m0c^2? Thanks.

In the Photoelectric effect what is the threshold frequency dependent on? This isn't homework I was just pondering. Is it the binding forces between the electron and the nuclues or is it dependent of a property of the photon?

What is the equation used to solve for the threshold frequency? Is the threshold frequency the minimum amount of energy requird to free an electron from the nucleus?

Can anyone help me find information on the percolation threshold, i.e for when particle concentration is increased to a point when electrical pathways are created and resistance decreases by many orders, for metals loaded polymers. Cheers :smile: :-p :approve: :zzz: :blushing...

Did that make any sense at all? The problem goes, and I do my best to translate from Enlish from Swedish: The mass of the intermediate vector boson Z is 97,1 times the mass of a protone, whos energy "at rest" is 938 MeV. a) Calculate the threshold temperature of Z. b) Calculate how long...

Dear all The question is : A certain material has a work function of 0.4eV. What is the energy of a single photon of electromagnetic radiation at the threshold frequency for liberation of photoelectrons? Would u give me some hint how to find the threshold frequency at first ?? thanks...