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

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

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:

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

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?

Which of the following is an arrangement of increasing value of $\mathrm{e}/\mathrm{m}$ (with respect to magnitude only): 
 

Neutron scattering experiments have shown that the radius of the nucleus of an atom is directly proportional to the cube root of the number of nucleons in the nucleus. From ${}_3{}^7\mathrm{Li}$ to ${}_{76}{}^{189}\mathrm{Os},$ What is the radius?

An oil drop has $6.4\times {10}^{-19}\mathrm{C}$ charge. The number of electrons in this oil drop are

The ratio of the $\left(\frac{\mathrm{e}}{\mathrm{m}}\right)$ (specific charge) values of a electron and an $\mathrm{\alpha }-$particle is

Which is not true with respect to cathode rays?

The relative charge on an atom having $17$ protons, $18$ neutrons and $18$ electrons is: