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
Answer:
The absolute value of the angular deviation is 39.3°.
Explanation:
Given that,
Current = 1.1 A
Distance = 0.9 cm
Magnetic field = 20μT
We need to calculate the magnetic field due to wire
Using formula of magnetic field
Put the value into the formula
We need to calculate the absolute value of the angular deviation
Using formula of direction
Hence, The absolute value of the angular deviation is 39.3°.
Answer:
8.33 meters/sec.
Explanation:
distance = 250 meters
time = 30 sec.
velocity = distance / time
= 250 meters
30 sec.
= 8.33 meters/sec.
Given,
Effort force = 120 N
Load force= 1050 N
Mechanical advantage of a pulley is given by the ratio of load force to the effort force.
Therefore, the mechanical advantage of the given pulley is 8.75.
The correct answer is 223 days.
The relationship between the duration of revolution and the separation between the sun is shown by Kepler's third law. Using the notions of circular motion and the gravitational and centripetal forces, we may obtain this equation.
According to Kepler's third rule, the semi-major axis of an orbit is linked to the orbital period of a planet around the sun as follows:
p² = a³
where an is the semi-major axis/distance to the star and p is the orbital period in years.
It is said that a = 0.72 AU for Venus.
P= √(0.72 AU)^3 = 0.61 years.
365 days in a year = 222.9 ≈ 223 days.
To learn more about Kepler's third rule refer the link:
brainly.com/question/1608361
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