Characteristic Spectrum

Q.

Explain the energy level diagram for electronic transitions.

Q. Calculate the de-Broglie wavelength associated with the electron in the $2^{nd}$ excited state of the hydrogen atom. The ground state energy of the hydrogen atom is $13.6\text{eV}$.

Q. As an electron makes a transition from an excited state to the ground state of a hydrogen−like atom/ion

1. its kinetic energy increases but potential energy and total energy decrease
2. kinetic energy, potential energy and total energy decrease
3. kinetic energy decreases, potential energy increases but total energy remains same
4. kinetic energy and total energy decrease but potential energy increases

Q.

De broglie wavelength associated with an electron accelerated through a potential difference of $200v$ is nearly

Q. Electrons with energy 80 keV are incident on the tungsten target of an X-ray tube. K shell electrons of tungsten have ionization energy 72.5 keV. X-rays emitted by the tube contain only

1. A continuous X-ray spectrum (Bremsstrahlung] with all wavelengths
2. The characteristic X-rays spectrum of tungsten
3. A continuous X-ray spectrum (Bremsstrahlung) with a minimum wavelength of $\sim 0.155\dot{A}$
4. A continuous X-ray spectrum (Bremsstrahlung) with a minimum wavelength of $\sim 0.155\dot{A}$ and the characteristic X-ray spectrum of tungsten

Q.

The wavelength of $K_{\alpha }$ line from an element of atomic number 41 is $\lambda$. Then the wavelength of $K_{\alpha }$ line of an element of atomic number 21 is

1. $4\lambda$

2. $\frac{\lambda }{4}$

3. $3.08\lambda$

4. $0.26\lambda$

Q.

An electron is accelerated from rest through a potential difference of $Vvolt$. If the de Broglie wavelength of the electron is $1.227\times {10}^{-2}nm$, the potential difference is

Q.

Explain the energy level diagram in detail.

Q. The intensity of x-rays from Coolidge tube is plotted against wavelength $\lambda$ for a molybdenum target at an accelerating voltage of 35 kV. The minimum wavelength found is ${\lambda }_0$ and the wavelength of the $K_{\alpha }$ line is ${\lambda }_{K\alpha }$. As the accelerating voltage is increased from 35 kV to 70 kV -

1. increases
2. decreases
3. decreases.
4. increases.

Q. Whenever a hydrogen atom emits a photon in the Balmer series,

1. It may emit another photon in the Brackett series.
2. It may emit another photon in the Lyman series
3. It need not emit any one more photon
4. It may emit another photon in the Paschen series

Q.

State the charge on an electron in coulomb.

Q. The $K_{\alpha }$ X-ray emission line of tungsten occurs at $\lambda =0.021$ nm. The energy difference between K and L levels in this atom is about

1. 1.2 MeV
2. 59 KeV
3. 0.51MeV
4. 13.6 eV

Q. How to solve: The energy required to dislodge electron from excited isolated H-atom, IE1=13.6eV is

Q.

The energy of K-alpha characteristic X-Ray is:

1. $E_k-E_l$

2. $E_l-E_k$

3. $E_k$

4. $E_l$

Q. The energy level diagram of $K_{\alpha }$ x-ray emission is shown here. What is the correct inference?

1. The arrow in the diagram represents the jump of an electron from the K shell to the L shell.
2. The energy levels represent the energies of the atom when one electron is missing from respective shell.
3. The energy of the atom in K shell is lesser than its energy in L shell, but the diagram shows K shell at higher energy; hence the diagram is incorrect.
4. An x-ray carrying about 17 keV of energy will be radiated in the transition.

Q.

A sample of paramagnetic salt contains 2.0 × 10²⁴ atomic dipoles each of dipole moment 1.5 × 10⁻²³ J T⁻¹. The sample is placed under a homogeneous magnetic field of 0.64 T, and cooled to a temperature of 4.2 K. The degree of magnetic saturation achieved is equal to 15%. What is the total dipole moment of the sample for a magnetic field of 0.98 T and a temperature of 2.8 K? (Assume Curie’s law)

Q. In an $X-$ ray tube, the accelerating voltage is $20\text{kV}$. Two targets $\text{A}$ and $\text{B}$ are used one by one. For $\text{A}$ the wavelength of the $K_{\alpha }$ line is $62\text{pm}$, For $\text{B}$ the wavelength of the $L_{\alpha }$ line is $124\text{pm}$. The energy of the $\text{B}$ ion with vacancy in $M$ shell is $5.5\text{keV}$ higher than atom of $\text{B}$.
$[\text{Take}hc=12400\text{eV}\mathring{\text{A}}]$

1. Value of ${\lambda }_{min}$ is $0.62\mathring{\text{A}}$
2. $\text{A}$ will emit $K_{\alpha }-$photon
3. $\text{B}$ will emit $L-$ photons.
4. Minimum wavelengths $\left(\text{in}\mathring{\text{A}}\right)$ of the characteristic $X-$ray that will be emitted by $\text{B}$ is $0.8\mathring{\text{A}}$

Q.

For a given material, the energy and wavelength of characteristic x-rays satisfy:

1. > >
2. > >
3. > >
4. > >

Q. The wavelength $\lambda$ of $K_{\beta }$ X-Ray is given by:

1. 
2. 
3. 
4. 

Q.

Give the usefulness of the energy level diagram of an electron in an atom.

Q.

An atom gets most energetic when:

1. The Electron is not at all removed

2. The Electron is removed from K shell

3. The Electron is removed from L shell

4. The Electron is removed from the highest shell

   
   

Q.

What is an energy level diagram?

Q. The wavelength of $K_{\alpha }$ and $L_{\alpha }$ X-Rays of a material are 20 pm and 140 pm respectively. Find the wavelength of $K_{\beta }$ X-Ray of the material.

1. 12.5 pm
2. 15.5 pm
3. 17.5 pm
4. 19.5 pm

Q. What is meant by pair production and annihilation ?

Q.

The energy of K-alpha characteristic X-Ray is:

1. El

2. Ek-El

3. El-Ek

4. Ek

Q. The $K_{\alpha }$ x-ray of molybdenum has wavelength 0.071 nm. If the energy of a molybdenum atom with a Kelectron knocked out is 23.32 keV, what will be the energy of this atom when an Lelectron is knocked out? If required, take hc = 1242 eV.nm.

1. 16.37 keV
2. 5.82 keV
3. 62.02 keV
4. 9.45 keV

Q. The $K_{\propto }$ X - ray emission line of tungsten occurs at $\lambda$ = 0.021nm. The energy difference between K and L levels in this atom is about

1. 136 eV
2. 0.51 MeV
3. 1.2 MeV
4. 59 keV

Q. The $K_{\alpha }$ x-ray emission line of tungsten occurs at $\lambda$ = 21 pm. What is the energy difference between $E_K$ and $E_L$ levels in this atom (MeV refers to mega electron volts;1MeV = ${10}^6$ eV and hc = 1242 eVnm)?

1. 0.59 MeV
2. 1.2 MeV
3. 59 KeV
4. 13.6 eV

Q. Dielectric strength of a dielectric material depends on which of the following?

1. The electrodes with which the electric field is applied,
2. The respective geometries of the dielectric
3. The electric field which is applied
4. All of the above

Q.

The wavelength of L-alpha characteristic X-Ray is :

1. Directly proportional to Ek-El

2. Inversely proportional to El-Em

3. Directly proportional to El-Ek

4. Directly proportional to El-Em