Discovery of Sub-Atomic Particles

Protons are discovered by 

Find the total mass(in mg) of neutrons in $7 \mathrm{mg}$ of ${}^{14}\mathrm{C}$. (Assume the mass of a neutron$=$mass of a hydrogen atom)

Report your answer as the nearest integer.

_____ and neutron are found inside the nucleus.

Among the following, the correct statement about cathode ray discharge tube is

 

An atom having atomic mass number $13$ has $7$ neutrons. What is the atomic number of the atom?

Which of the following substances, shows the properties of phosphorescent?

The electrical discharge through the gases could be observed only at

Which of the following is not a pair of isodiaphers:

The $\mathrm{e}/\mathrm{m}$ ratio is maximum for :-

If ${\mathrm{S}}_1$ be the specific charge of cathode rays and ${\mathrm{S}}_2$ be that of positive rays, then which is true :-

A dipositive ion has $16$ protons. What is the number of electrons in its tetrapositive ion?

The mass-charge ratio for ${\mathrm{A}}^{+}$ ion is $1.97\times {10}^{-7} \mathrm{kg} {\mathrm{C}}^{-1}$ then mass of $\mathrm{A}$ atom is:-

Describe the experiment which led to the discovery of the proton.

Consider $\mathrm{\alpha }$ -particles, $\mathrm{\beta }$ -particles and $\mathrm{\gamma }$-rays, each having an energy of $0.50 \mathrm{MeV}.$ The increasing order of penetration power is:

${}_{90}{}^{234}\mathrm{Th}$ disintegrates to give ${}_{82}{}^{206}\mathrm{Pb}$ as the final product. How many alpha and beta particles are emitted during this process? Express answer as number of $\alpha$-particles $+$ number of $\beta$-particle emitted.

The increasing order for the values of ${\mathrm{em}}^{-1}$ (charge/mass) is:

Why is the cathode ray tube experiment not conducted at atmospheric pressure?

The ratio of specific charge of an electron to that of a proton is

A certain photochemical reaction is found to require 8.1 x 10^-19energy per water molecule.
Calculate the number of photons (per water molecule) of light with wavelength of 2.21x 10^-6 mthat is required to initiate the reaction​ ?

What are cathode rays?