write evidences in favour of bohr,s model of atoms in very easy language
Answers
(i) Ratio of mass of electron to the mass of the proton:
Determination of
H
m
M
:
The difference in the Rydberg constant for H- atom and He- atom can be used to
compute the ratio of the mass of the electron to the mass MH of the hydrogen nucleus
(proton).
We have
........................(1)
1
And ..............(2)
1
H
H
He
He
R R
m
M
R R
m
M
α
α
=
+
=
+
Where Rα = Rydberg constant for an infinitely heavy nucleus.
Since the mass of the He - nucleus is four times that of the H-atom; we can write,
( )
7 1
7 1
1
4
(1) (2)
1
4 4
4 1
1 1.09677 10
1 1836 1.09622 10
4
He
H
H HH
He H
H
He H H
H He H He
R R
m
M
m
R M Mm
R Mm m
M
m R R R m
M R m R R
α
−
−
=
+
∴ ⇒
+
+ = = + +
− = ×
⇒= =
= × −
÷
This agrees with the expected result.
Thus knowing RH and RHe the ratio
H
m
M
Again The specific charge of electron;