$\alpha$-particles of energy $400 \, KeV$ are bombarded on a nucleus of $_{82}Pb$. In the scattering of $\alpha$-particles, what will be the minimum distance of approach from the nucleus?

According to Richard Feynman,matter is made of which constituent particles? Why is it important? Write the atomic hypothesis.

The distance of the closest approach of an alpha particle fired at a nucleus with kinetic energy $K$ is $r_{0}$. The distance of the closest approach when the $\alpha$-particle is fired at the same nucleus with kinetic energy $2K$ will be . . . . . . .

$A$ beam of fast-moving alpha particles was directed towards a thin gold foil. The parts $A'$,$B'$,and $C'$ of the transmitted and reflected beams corresponding to the incident parts $A$,$B$,and $C$ of the beam are shown in the adjoining diagram. The number of alpha particles in:

State the postulates of Dalton's atomic theory.

An $\alpha$-particle of energy $5 \text{ MeV}$ is scattered through $180^{\circ}$ by a gold nucleus. The distance of closest approach is of the order of: