A beam of electrons of energy E scatters from a target having atomic specing of 1Å. The first maximum intensity occurs at `theta = 60^@`. The E (in eV) is ___________
(Planck constant `h = 6.64 xx 10^(-34) Js`,
`1eV = 1.6 xx 10^(19)J`,
electron mass `m = 9.1 xx 10^(-31) kg`)

A neutron beam of energy E scatters from atoms on a surface with a spacing d=0.1nm. The first maximum of intensity in the reflected beam occurs at theta=30^(@) . What is the kinetic energy of E of the beam in eV?

If the kinetic energy of an electron is 4.55 xx 10^(-25)J , find its wavelength (Planck's cosntant, h = 6.625 xx 10^(-34) kgm^(2)s^(-1), m = 9.1 xx 10^(-31)kg ).

When an electron in hydrogen atom is excited, from its 4 th to 5 th stationary orbit, the change in angular momentum of electron is (Planck's constant: h = 6.6 xx 10^(-34) J-s )

Uncertainty in position of a particle of 25 g in space is 10^(-5) m. Hence, uncertainty in velocity (m s^(-1)) is (Planck's constant h=6.6 xx 10^(-34)Js)

An electron beam has a kinetic energy equal to 100 eV . Find its wavelength associated with a beam , if mass of electron = 9.1 xx 10^(-31) " kg and 1 eV " = 1.6 xx 10^(-19) J . (Planks's constant = 6.6 xx 10^(-34) J-s)

If de Broglie wavelength of an electron is 0.5467 Å, find the kinetic energy of electron in eV. Given h=6.6xx10^(-34) Js , e= 1.6xx10^(-19) C, m_e=9.11xx10^(-31) kg.

In an experiment tungsten cathode which has a threshold 2300 Å is irradiated by ultraviolet light of wavelength 1800Å . Calculate (i) Maximum energy of emitted photoelectron and (ii) Work function for tungsten. (Mention both the results in electron-volts) Given Planck's constant h=6.6 xx 10^(-34) J-sec , 1eV = 1.6 xx 10^(-19) J and velocity of light c= 3xx10^(8)m//sec

Wave property of electron implies that they will show diffraction effected . Davisson and Germer demonstrated this by diffracting electron from crystals . The law governing the diffraction from a crystals is obtained by requiring that electron waves reflected from the planes of atoms in a crystal interfere constructiely Electron accelerated by potential V are diffracted from a crystal if d = 1 Å and i = 30^(@), V should be about (h = 6.6 xx 10^(-34) Js, m_(e) = 9.1 xx 10^(-31) kg , e = 1.6 xx 10^(-19)C)

What is the number of significant figures in Avogadro's number (6.0 xx 10^(23)) and Planck's constant (6.62 xx 10^(-34) J s) .