What is an `alpha`-particle?

Alpha particle is

What is the ratio of mass of a gold atom and an alpha -particle ?

A uranium 238 nucleus, originally at rest, emits and alpha particle. The alpha particle travels with a speed of v m/s. What is the recoil speed of the residual necleus?

Nucleus ._(92)U^(238) emits alpha -particle (._(2)He^(4)) . alpha- particle has atomic number 2 and mass number 4. At any instant alpha- particle is at distance of 9 xx 10^(-15)m from the centre of nucleus of uranium. What is the force on alpha- particle at this instant? ._(92)U^(238) rarr ._(2)He^(4) + ._(90)Th^(234)

Charge on an alpha -particle is

A proton and and alpha - particle are accelerated through a potential difference of 100 V . The ratio of the wavelength with the proton to that associated to that associated with an alpha - particle is