# Properties of Alpha particle

1. An alpha particle is nothing but a helium nucleus consisting of two protons and two neutrons with two unit of positive charge.
2. $\alpha$ particle coming out of a radioactive substances have very high velocity which might range from $1.4\times 10^7 to 1.7\times 10^7 m/s$. Their path is a straight line and their motion can be observed in Wilson’s cloud chamber.
3. $\alpha$ particle is capable of producing intense ionization in the gas through which it passes. Its ionization power is 100 times greater than $\beta$ particle and 10,000 times bigger than that of $\gamma$ rays.
4. It can affect photographic plate but its really week and feeble.
5. $\alpha$ particle can produce fluorescence effect when they fall on substance like zinc sulphide or barium platinocyanide.  This fluorescence can be observed through the microscope.
6. $\alpha$ particle is deflected by electric and magnetic fields and this shows that $\alpha$ particle are charged particles.
7. $\alpha$ particles are scattered by heavy elements like gold.
8. $\alpha$ particle produces heating effect which is produced by stoppage of $\alpha , \beta , \gamma$ rays by the radioactive substance.
9. The E/M value of alpha particle was found by Rutherford to be half of that for hydrogen ion. The charge on each alpha particle was found to be twice that of a hydrogen ion. The mass of the $\alpha$ particle was shown to be four times that of hydrogen. Therefore $\alpha$ particle is the nucleus of hydrogen atom.