The particle with mass equal to 9.1x10^(-31) kg and charge equal to -1.6x10^(-19) is: (a) `beta` `` (b) `gamma` (c) `alpha` (d) X rays ` `
This would be a beta particle, as the quantities given represent the mass of an electron in kilograms and the charge of an electron in Coulombs. Beta particles are high energy electrons, so they have the mass and charge of an electron.
In the context of atoms, it's more common to use amu (atomic mass units) to express the mass of the subatomic particles, in which case an electron has a mass of 5.5x10^(-4) amu.
Of the other choices, only c, alpha, is a particle. It's equivalent to a helium nucleus, containing two protons and two neutrons. It's rest mass is
6.64424 X10^(-27) kg or 3.7273 amu
and it's charge is positive and twice the magnitude of the charge of an electron.
The other two choices, b (gamma) and d (X-rays), are both forms of electromagnetic radiation, so they are waves rather than particles.