2.
The spines of a European hedgehog protect it from predators.
3.
'Wooden spoon' is the imaginary prize for the last person in a race
Answers
Explanation:
a
(
Z
−
b
)
,
ν=a(Z−b),
which gives
λ
=
c
ν
=
c
a
2
(
Z
−
b
)
2
.
λ=cν=ca2(Z−b)2.
Thus, the wavelength of emitted X-rays decreases with increase in
Z
Z. The cut-off wavelength of continuous X-rays corresponds to maximum energy of electron in X-ray tube. It is given by
h
c
/
λ
=
e
V
,
hc/λ=eV,
where
V
V is the accelerating potential. The intensity of X-rays depends on the number of electrons striking the target per second, which, in turn, depends on the electrical power given to the X-ray tube as energy of each electron is
e
V
eV.
Questions on Moseley's Law
Question: If 178.5 pm is the wavelength of X-ray line of copper (atomic number 29) and 71 pm is the wavelength of the X-ray line of molybdenum (atomic number 42) then the value of a and b in Moseley's equation are
A.
a
=
7
×
10
7
H
z
1
/
2
a=7×107Hz1/2, b=1.0
B.
a
=
5
×
10
7
H
z
1
/
2
a=5×107Hz1/2, b=7.4
C.
a
=
5
×
10
7
H
z
1
/
2
a=5×107Hz1/2, b=1.4
D.
a
=
7
×
10
7
H
z
1
/
2
a=7×107Hz1/2, b=7.4
Select and click to check answer
Question: Moseley's Law for characteristic X-rays is
√
ν
=
a
(
Z
−
b
)
ν=a(Z−b). In this formula
A. both a and b are independent on the material.
B. a is independent but b depends on the material.
C. b is independent but a depends on the material.
D. both a and b depend on the material.
Select and click to check answer
Related Topic
Characteristic and Continuous X-rays | Problems | IIT JEE
References and External Links
Concepts of Physics Part 2 by HC Verma (Link to Amazon)
IIT JEE Physics by Jitender Singh and Shraddhesh Chaturvedi
X-ray Fluorescence and Moseley’s Law (pdf article on X-rays, Moseley's Law and Moseley's Experiments)
The Physical (in)significance of Moseley's Screening Parameters, (journal article in pdf by K Razi Naqvi)
One hundred years of Moseley’s law: An undergraduate experiment with relativistic effects (pdf)At the present time, the widespread use of masks everywhere is not supported by high-quality scientific evidence, and there are fabric