The first model of the atom was developed by JJ Thomson in 1904, who thought that atoms were composed purely of negatively charged electrons. This model was known as the 'plum pudding' model.
This theory was then disproved by Ernest Rutherford and the gold foil experiment in 1911, where Rutherford shot alpha particles at gold foil, and noticed that some went through and some bounced back, implying the existence of a positive nucleus.
In 1913, Niels Bohr proposed a model of the atom where the electrons were contained within quantized shells that orbited the nucleus. This was because it was impossible for the cloud of negative electrons proposed by Rutherford to exist, as the negative electrons would be drawn to the positive nucleus, and the atom would collapse in on itself.
In 1926, the Austrian physicist Erwin Schrödinger created a quantum mechanical model of the atom by combining the equations for the behavior of waves with the de Broglie equation to generate a mathematical model for the distribution of electrons in an atom.
However the model used today is closest to the Bohr model of the atom, using the quantized shells to contain the electrons.
For more info:
http://chemistry.about.com/od/chemistryglossary/a/debroglieeqdef.htm
Pumice is used for cleaning foot. Foot are wet with warm water and then scrub by pumice so that hard and dry skin can be removed. It is quite effective in cleaning skin.
Pumice is also used as light weight material in concrete mix. Due to it porous texture, it is a good light weight material.
Answer:
Faraday's law
, he direction of the magnetic field changes by 180º, in the polarity inversion processes, induces a voltage.
Explanation:
For this exercise let's use Faraday's law
E = - dФ / dt
Ф = B.A = B A cos θ
where B is the magnetic field, A is the area and θ is the angle between the field line and the normal to the area.
We can see that an electromotive force (voltage) is indexed when there is a variation of the field B, a variation of the area and change of the angle or when there is a combinational of them.
In this case, the magnitude of the field is constant, as the wire is rigid metal, the area is constant, but the direction of the magnetic field changes by 180º, in the polarity inversion processes, for which reason each change induces a voltage.
If a voltage is created in the ring, which has a resistance, a current is also generated in it.
Therefore the answer is If a current is created in the hoop
