Problem 18.43 Part A Find an expression for the mean free path of an electron th

Question

Problem 18.43

Part A

Find an expression for the mean free path of an electron through a gas.

Express your answer in terms of the given quantities.

Part B

Electrons travel 3 km through the Stanford Linear Accelerator (SLAC). In order for scattering losses to be negligible, the pressure inside the accelerator tube must be reduced to the point where the mean free path is at least 49 km . What is the maximum possible pressure inside the accelerator tube, assuming T = 21 ?C? Give your answer in both Pa and atm.

Express your answer using two significant figures.

Explanation / Answer

PART A:

Same as the expression given in the expression of mean free path

PART-B:

PV=NkT

P = NkT/V =

N is obtained from Mean Free path Expression , N = 1/(4*sqrt2*pi*wqqvelength/Vr^2)

P = kT/V * 1/(4*sqrt2*pi*mean free path/Vr *^2)

P = (1.38 × 10-23 * 294)/ ( 4*1.414*49000* 31^2* 10^-30) here we take He gas as SLAC is filled with Helium( atomic radius of He is 31 pm)

P = 15 Pa

P = 1.5 * 10^-4 atm

Related Questions

Navigate

• Browse (All)
• Browse P
• Subjects