The Scattering of Helium Atoms by a Solid Can Be

question 71

Short Answer

The scattering of helium atoms by a solid can be used to gain information about the lattice of atoms, provided the wavelength of the helium atoms is comparable to the dimensions of the lattice.What is the wavelength, in picometers, of a helium-4 atom with a kinetic energy of 0.10 eV.(mass of ⁴He = 4.0026 amu; 1 amu = 1.67 × 10^-24 g; 1 eV = 1.602 × 10^-19 J. h = 6.626 × 10^-34 J.s)

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Definitions:

Discount Rate

The interest rate used to discount future cash flows to their present value, often reflecting the cost of capital or the risk of the investment.

Present Value

The present evaluation of a future cash sum or series of cash receipts, factoring in a certain rate of return for discounting.

Interest Rate

The sum a lender charges a borrower to use assets, conveyed as a percentage of the principal's amount.

Present Value

The here and now valuation of a prospective future financial amount or series of cash flows, calculated with a certain return rate.