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:
0.42°
Explanation:
Using Snell's law of refraction which states that the ratio of the angle of sin of incidence to angle of sine of refraction is equal to a constant for a given pair of media. Mathematically,
Sin(i)/sin(r) = n
n is the refractive index of the medium
FOR VIOLET LIGHT:
n = 2.46
i = 51°
r = ?
To get r, we will use the Snell's law formula.
2.46 = sin51°/sinr
Sinr = sin51°/2.46
Sinr = 0.316
r = sin^-1(0.316)
rv = 18.42°
FOR RED LIGHT:
n = 2.41
i = 51°
r = ?
To get r, we will use the Snell's law formula.
2.41 = sin51°/sinr
Sinr = sin51°/2.41
Sinr = 0.323
r = sin^-1(0.323)
rd = 18.84°
The angular separation between these two colors of light in the refracted ray will be the difference between there angle of refraction.
Angular separation = rd - rv
= 18.84° - 18.42°
= 0.42°
Answer:
current in series is 2.50 mA
current in parallel is 13.51 mA
Explanation:
given data
voltage = 5 V
resistors R1 = 1.5 kilo ohms
resistors R2 = 0.5 kilo ohms
to given data
current flow
solution
current flow in series is express as here
current = voltage / resistor .................1
put here all value in equation 1
current = 5 / (1.5 + 0.5)
current = 5 / 2.0
so current = 2.50 mA
and
current flow in parallel is express as
current = voltage / resistor ....................2
put here all value in equation 2
current = 5 / (1/ (1/1.5 + 1/0.5))
current = 5 / 0.37
so current = 13.31 mA
Answer:
s=1721.344m ,v=104.96m/s.
Explanation:
using thr equation of motion;
u=0, plane starts from rest,
s=1721.344m
v=u+at
v=0 +3.2*32.8
v=104.96m/s
