An α-particle moving with initial kinetic energy K towards a nucleus of atomic number Z approaches a distance d at which it reverses its direction. Obtain the expression for the distance of closest approach d in terms of the kinetic energy of α-particle K.
Differentiate between distance of closest approach and impact parameter.
Determine the distance of closest approach when an alpha particle of kinetic energy 3.95 MeV approaches a nucleus of Z = 79, stops and reverses its directions.
In an experiment on α-particle scattering by a thin foil:
Draw a plot showing the number of particles scattered versus the scattering angle θ.
Why is it that a very small fraction of the particles is scattered at θ > 90°?
Write two important conclusions that can be drawn regarding the structure of the atom from the study of this experiment.
Define distance of closest approach.
State the postulates of Bohr's model of hydrogen atom.
Derive the expression for Bohr radius.
Find the ratio of the longest and the shortest wavelengths amongst the spectral lines of Balmer series in the spectrum of hydrogen atom.
Draw a schematic arrangement of the Geiger-Marsden experiment for studying a-particle scattering by a thin foil of gold.
Describe briefly by drawing trajectories of the scattered α-particles, how this study can be used to estimate the size of the nucleus?
Which state of the triply ionised beryllium (Be3+) has the same orbital radius as that of the ground state of hydrogen?
Monochromatic radiation of wavelength 975 excites the hydrogen atom from its ground state to a higher state. How many different spectral lines are possible in the resulting spectrum? Which transition corresponds to the longest wavelength amongst them.
Draw a schematic arrangement of Geiger Marsden experiment showing the scattering of α-particles by a thin foil of gold.
Why is it that most of the α-particles go right through the foil and only a small fraction gets scattered at large angles?
Draw the trajectory of the α-particle in the coulomb field of a nucleus.
What is the significance of impact parameter and what information can be obtained regarding the size of the nucleus?
Estimate the distance of closest approach to the nucleus (Z = 80) if a 7.7 MeV α-particle before it comes momentarily to rest and reverses its direction.
An -particle having kinetic energy K approaches a nucleus of atomic number Z. It gets close to the nucleus and then approaches a distance (d) and reverses its direction. Obtain an expression for the distance of closest approach (d) in terms of kinetic energy of the -particle.
A proton and an alpha particle approach a target nucleus in head-on position, with equal velocities. Find the ratio of their distances of closest approach to the target nucleus.