12th Grade > Physics
X - RAYS MCQs
Total Questions : 12
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Answer: Option A. -> (λKα−λ0) increases
:
A
The Kα peak corresponds to radiation when the atom transitions between two energy levels due to an internal jump of an electron from the Lshell to the Kshell. It is characteristic for a particular element and will not depend on any external parameters, like the accelerating potential.
But increasing the accelerating potential from 35kV to 70kV will now allow x-rays carrying energies in the range 35-70 eV, which was not allowed earlier. There will now be a higher cut-off on the energy, and hence, a lower cutoff on the wavelength (since E∞1λ). The new cut-off wavelength λ0 will be lower than λ0, and farther from λKα.
Thus, among the given options, the only thing that will change when you increase the accelerationg potential is that (λKα−λ0) will increase.
:
A
The Kα peak corresponds to radiation when the atom transitions between two energy levels due to an internal jump of an electron from the Lshell to the Kshell. It is characteristic for a particular element and will not depend on any external parameters, like the accelerating potential.
But increasing the accelerating potential from 35kV to 70kV will now allow x-rays carrying energies in the range 35-70 eV, which was not allowed earlier. There will now be a higher cut-off on the energy, and hence, a lower cutoff on the wavelength (since E∞1λ). The new cut-off wavelength λ0 will be lower than λ0, and farther from λKα.
Thus, among the given options, the only thing that will change when you increase the accelerationg potential is that (λKα−λ0) will increase.
Answer: Option A. -> hcEK−EM
:
A
Kβ characteristic X-Ray phton is emitted when an electron from the M shell jumps to fill the electronic vacancy created in K shell.
Now, if we refer to the Energy Level Diagram, we find that The atomic energy when there is a vacancy in K shell is EK.
Also the atomic energy when the vacancy gets created in M shell is EM.
We see that EM < EK.
So the atom has lost this energy. How much ?
EK−EM
This energy appears as the energy of Kβ characteristic X-Ray phton.
Hence hcλKβ=EK−EM.
Which gives,
1λKβ=EK−EM.
:
A
Kβ characteristic X-Ray phton is emitted when an electron from the M shell jumps to fill the electronic vacancy created in K shell.
Now, if we refer to the Energy Level Diagram, we find that The atomic energy when there is a vacancy in K shell is EK.
Also the atomic energy when the vacancy gets created in M shell is EM.
We see that EM < EK.
So the atom has lost this energy. How much ?
EK−EM
This energy appears as the energy of Kβ characteristic X-Ray phton.
Hence hcλKβ=EK−EM.
Which gives,
1λKβ=EK−EM.
Answer: Option A. -> The atomic energy levels
:
A
Atomic energy levels decide the amount of energy released in an electronic transition, and the wavelength of a photon is dependent on their energy.
:
A
Atomic energy levels decide the amount of energy released in an electronic transition, and the wavelength of a photon is dependent on their energy.
Answer: Option C. -> 17.5 pm
:
C
For the wavelength of Kα x-rays; hcλ1 = EK−EL
for the wavelength of Lα x-rays; hcλ2 = EL−EM
or the wavelength of Kβ x-rays; hcλ3 = EK−EM
Now,
If we add the first two equation we get :
hc(1λ1+1λ2)=EK−EM
Now from equations iii) and iv)
hcλ3=hc(1λ1+1λ2).
We get;
1λ3=(1λ1+1λ2).
Or,
1λ3=(120+1140)pm−1
Or,
λ3=2800160pm.
Or,
λ3 = 17.5 pm
:
C
For the wavelength of Kα x-rays; hcλ1 = EK−EL
for the wavelength of Lα x-rays; hcλ2 = EL−EM
or the wavelength of Kβ x-rays; hcλ3 = EK−EM
Now,
If we add the first two equation we get :
hc(1λ1+1λ2)=EK−EM
Now from equations iii) and iv)
hcλ3=hc(1λ1+1λ2).
We get;
1λ3=(1λ1+1λ2).
Or,
1λ3=(120+1140)pm−1
Or,
λ3=2800160pm.
Or,
λ3 = 17.5 pm
Answer: Option B. -> The energy of atom when electron is removed from that particular shell
:
B
The energies marked in the diagram are the energies of the atom when a vacancy of electron is created in particular shells.
For example, the energy marked as EKis the energy of atom when one electron from the K shell is removed. And so on.
It is interesting to note that the energy of the atom with one vacancy in K shell is higher; and as we move towards the higher shells, the energies of the atom with vacancies in those shells decrease. Also, the energy is zero when the atom is in its ground state.
This can be understood simply, as the K shell electrons are bound to the nucleus most strongly; this force decreases as we move to higher shells. Hence, to remove an electron from the lowermost shell (K) maximum amount of energy is required to be supplied, this amount will decrease as we move towards higher shells; for the same reason.
In the ground state (no electrons removed) the atom’s energy will be the least, which is taken to be zero.
:
B
The energies marked in the diagram are the energies of the atom when a vacancy of electron is created in particular shells.
For example, the energy marked as EKis the energy of atom when one electron from the K shell is removed. And so on.
It is interesting to note that the energy of the atom with one vacancy in K shell is higher; and as we move towards the higher shells, the energies of the atom with vacancies in those shells decrease. Also, the energy is zero when the atom is in its ground state.
This can be understood simply, as the K shell electrons are bound to the nucleus most strongly; this force decreases as we move to higher shells. Hence, to remove an electron from the lowermost shell (K) maximum amount of energy is required to be supplied, this amount will decrease as we move towards higher shells; for the same reason.
In the ground state (no electrons removed) the atom’s energy will be the least, which is taken to be zero.
Answer: Option A. -> 0.59 MeV
:
A
Kαx-ray emission takes place when an electron jumps from L-shell to fill a vacancy created in K-shell.
Now EKis the energy of the atom when vacancy is in K-Shell, and ELIs the energy of the atom when vacancy is created in L-Shell. Also, EK >ELSo, when vacancy shifts from K to L, according to our agrument, the atomic energy decreases. How much ?
EK−EL.
This difference results into X-ray photon.
Hence connecting the dots we can conclude that ; The energy difference between K and L levels is the energy of the photon.
Mathematically;
EK−EL=Ephoton
Now,
EK−EL=hcλ
Which gives after putting in the values;
EK−EL=1242eVnm0.0021nm
Final calculations leads us to our answer;
EK−EL=591428eV
Or,
EK−EL=0.59MeV
:
A
Kαx-ray emission takes place when an electron jumps from L-shell to fill a vacancy created in K-shell.
Now EKis the energy of the atom when vacancy is in K-Shell, and ELIs the energy of the atom when vacancy is created in L-Shell. Also, EK >ELSo, when vacancy shifts from K to L, according to our agrument, the atomic energy decreases. How much ?
EK−EL.
This difference results into X-ray photon.
Hence connecting the dots we can conclude that ; The energy difference between K and L levels is the energy of the photon.
Mathematically;
EK−EL=Ephoton
Now,
EK−EL=hcλ
Which gives after putting in the values;
EK−EL=1242eVnm0.0021nm
Final calculations leads us to our answer;
EK−EL=591428eV
Or,
EK−EL=0.59MeV
Answer: Option B. -> 5.82 keV
:
B
In our notation of energy levels, an energy EX will mean the energy of the atom when there's a missing electron in the Xshell ( X = K, L, M, N,....). Writing quantitatively.
E(Kα) = EK−EL
⇒EL=EK−E(Kα)
⇒EL=EK−(hcλKα)
⇒EL=23.32keV−(1242eV.nm0.071nm)=23.32keV−17.5eV
⇒EL=5.82keV.
:
B
In our notation of energy levels, an energy EX will mean the energy of the atom when there's a missing electron in the Xshell ( X = K, L, M, N,....). Writing quantitatively.
E(Kα) = EK−EL
⇒EL=EK−E(Kα)
⇒EL=EK−(hcλKα)
⇒EL=23.32keV−(1242eV.nm0.071nm)=23.32keV−17.5eV
⇒EL=5.82keV.
Answer: Option B. -> Behaviour of radiations being generated inside Crook’s tube
:
B
Sneaking through history, we understand that Mr. Roentgen was looking for the behaviour of the radiation being generated inside the Crook’s tube.
:
B
Sneaking through history, we understand that Mr. Roentgen was looking for the behaviour of the radiation being generated inside the Crook’s tube.
Answer: Option A. -> 1-x, 2-y, 3-z
:
A
This is a definition based question.
We defined as following :
Kα : When electronis transition takes place from L-shell to K-shell or vacancy shifts from K-shell to L-shell (this is what the energy level diagram indicates)
Kβ :When electronis transition takes place from M-shell to K-shell or vacancy shifts from K-shell to M-shell (this is what the energy level diagram indicates)
Kγ :When electronis transition takes place from N-shell to K-shell or vacancy shifts from K-shell to N-shell (this is what the energy level diagram indicates)
Got the answer!!
:
A
This is a definition based question.
We defined as following :
Kα : When electronis transition takes place from L-shell to K-shell or vacancy shifts from K-shell to L-shell (this is what the energy level diagram indicates)
Kβ :When electronis transition takes place from M-shell to K-shell or vacancy shifts from K-shell to M-shell (this is what the energy level diagram indicates)
Kγ :When electronis transition takes place from N-shell to K-shell or vacancy shifts from K-shell to N-shell (this is what the energy level diagram indicates)
Got the answer!!
Answer: Option D. -> II > IV > III > I
:
D
It’s a very simple question. We have to compare the energy in all the four diagrams. Basically these diagrams represent an atom with different electronic configuration with, infact, an electron missing from a specific shell in each case. Proceeding organically, first of all let's say the energy in the first case (with each electron at its place) is x.
Now, in the second diagram the electron is removed from the K-shell. We need to supply energy to the atom to do this right? So let's say we supplied an energy ΔK.
So, the atom's energy now becomes x+ΔK.
Now in the third diagram the electron is removed from M shell. We need to supply energy even for that. Let's say that energy is ΔM.
So, atom’s energy becomes x+ΔM.
In the fourth diagram, similarly after removing electron from L-shell the atomic energy becomes x+ΔL.
Now, we understand that it is tougher to remove the electron which is closer to the nucleus as it is more strongly bounded with the nucleus. To remove the electron from K-shell we need to supply the highest amount of energy, and to remove an electron from the M-shell we need to supply the least amount of energy. Mathematically,ΔK >ΔL >ΔM
Hence the energy of the atom will be in the order: II > IV > III > I.
:
D
It’s a very simple question. We have to compare the energy in all the four diagrams. Basically these diagrams represent an atom with different electronic configuration with, infact, an electron missing from a specific shell in each case. Proceeding organically, first of all let's say the energy in the first case (with each electron at its place) is x.
Now, in the second diagram the electron is removed from the K-shell. We need to supply energy to the atom to do this right? So let's say we supplied an energy ΔK.
So, the atom's energy now becomes x+ΔK.
Now in the third diagram the electron is removed from M shell. We need to supply energy even for that. Let's say that energy is ΔM.
So, atom’s energy becomes x+ΔM.
In the fourth diagram, similarly after removing electron from L-shell the atomic energy becomes x+ΔL.
Now, we understand that it is tougher to remove the electron which is closer to the nucleus as it is more strongly bounded with the nucleus. To remove the electron from K-shell we need to supply the highest amount of energy, and to remove an electron from the M-shell we need to supply the least amount of energy. Mathematically,ΔK >ΔL >ΔM
Hence the energy of the atom will be in the order: II > IV > III > I.