Early Atomic Models

In an atom, neutrons are present in the nucleus. 

In an atom ${}_{\text{13}}{\text{AI}}^{\text{27}}$, find the number of neutrons.

In an atom ${}_{\text{13}}{\text{AI}}^{\text{27}}$, find the number of electrons.

The gravitational force between a $\mathrm{H}$-atom and another particle of mass $m$ will be given by Newton's law $F=G\frac{M\cdot m}{r^2}$, where $r$ is in metre and

In an atom, electrons are present in the nucleus. 

In an atom the number of _____ is equal to the number of electrons that revolve around the nucleus

$\alpha$ - particle consists of

Rutherford deduced that Thomson ‘plum pudding’ model of the atom was certainly correct.

A standing wave in a string 35 cm long has a total of six nodes including those at the ends. Hence, wavelength of the standing wave is

Cotyledons are also called-

Which of the following properties of atom could be explained correctly by the Thomson Model of atom?

In the experiment for the determination of $\frac{e}{m}$ of electrons by the Thomson method, electric and magnetic fields are

In Thomson mass spectrograph, singly and doubly ionised particles from similar parabola corresponding to magnetic fields of 0.8 T and 1.2 T for a constant electric field. The ratio of masses of ionised particles will be