Answer:The mass of ball B is 10 kg.
Explanation;
Mass of ball A = 
Velocity of the ball A before collision:
Velocity of ball A after collision=
Mass of ball B= 
Velocity of the ball B before collision:
Velocity of ball B after collision=



The mass of ball B is 10 kg.
Density =mass/volume
density= (0.044kg/(11 x10^-6)
4000kg/m^3
Answer:
(a) Ferromagnet
Explanation:
Ferromagnetism is defined as the property by which certain magnets form the permanent magnets.
It is tone of the strong magnetism and it is common phenomenon of magnet in the everyday life of magnetism.
Permanent magnets are made up of ferromagnetic material, in this if the magnetic field is applied then this material is magnetized but do not losses its magnetic property after removal of external magnetic field.
Answer:
negative ion
Explanation:
An atom that has fewer neutrons than protons and more electrons than protons is a negative ion.
The positively charged particles in an atom are the protons
The negatively charged particles in an atom are the electrons.
The charge an atom carries depends on the balance between the number of protons and electrons in an atom.
- When the number of protons is more than the number of electrons, the atom is positively charged.
- When the number of electrons is more than the number of protons, the atom is negatively charged.
We can find the energy needed to ionize the hydrogen atom.
We can find the wavelength of a spectral line.
We can find the energy change of the electron moving between two levels.
The first atomic model to adequately explain the radiation spectra of atomic hydrogen was Bohr's model of the hydrogen atom. The atomic Hydrogen model was first presented by Niels Bohr in 1913. Rutherford's model of the hydrogen atom leaves several holes, which Bohr's model of the hydrogen atom tries to fill in.
It has a particular place in history since it introduced the quantum theory, which led to the development of quantum mechanics. Bohr proposed that electrons moved in predetermined orbits or shells with defined radii around the nucleus. It was impossible for electrons to reside between any shells other than those having a radius given by the equation below.


Learn more about hydrogen atom here;
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