For the same angle of incidence, the angle of refraction in three different media A, B and C are 10°, 25° and 40°
respectively. In which medium the velocity of light will be
maximum?
​

Media C

Explanation:

We know that ratio of sine of angle of incidence to the sine of refraction gives refractive index. Increases in refractive index increases the range of bending. Here angle of incidence is same in every case. The angle of refraction is greater in c. It has less refractive index and hence, light suffer less bending, which increases its speed.

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.