Tag: detection and recording of x-ray images

Questions Related to detection and recording of x-ray images

The minimum value of Compton wavelength shift is:

  1. $h/2 m _{0}c$

  2. $h/m _{0}c$

  3. $2h/m _{0}c$

  4. $zero$


Correct Option: A
Explanation:

$\lambda -\lambda ^{1}  =  \dfrac{h}{m _e c}\ (1+cos  \theta )$

$\Delta \lambda ^{1}  =  \dfrac{h}{m _e c}\ (1+cos  \theta )$

$cf   \theta = 0^{0}$

then  $\Delta \lambda = 0$

Consider a metal used to produced some characteristic $X-$rays. Energy of $X-$ray are given by $E$ and wavelength as represented by $\lambda$. Then which of the following is true:

  1. $E(K _{\alpha}) > E({K} _{\beta}) > E(K _{\gamma})$

  2. $E(M _{\alpha}) > E(L _{\alpha}) > E(K _{\alpha})$

  3. $\lambda (K _{\alpha}) > \lambda (K _{\beta}) > \lambda (K _{\gamma})$

  4. $\lambda (M _{ \alpha })>\lambda (L _{ \alpha })>\lambda (K _{ \alpha })$


Correct Option: B

The shortest wavelength of X-rays emitted from an X-ray tube depends on

  1. The current in tube

  2. The voltage applied to the tube

  3. The nature of the gas in tube

  4. The atomic number of the target material


Correct Option: B

The intensity of X-rays of wavelength $0. \mathring{A}$ reduces to one fourth on passing through $3.5 \ mm$ thickness of a metal foil. The coefficient of absorption of metal will be:-

  1. $0.2 \ mm^{-1}$

  2. $0.4 \ mm^{-1}$

  3. $0.6 \ mm^{-1}$

  4. $0.8 \ mm^{-1}$


Correct Option: A

In Compton effect, the quantity $\dfrac{h}{m _{e}c}$ is called

  1. Compton recovery wavelength

  2. Scattered wavelength of photon

  3. Compton wavelength of electron

  4. Compton wavelength of photon


Correct Option: C
Explanation:

$\lambda -\lambda ^{1}=\dfrac{h}{m _e c}(1-cos  \theta )$

where $\dfrac{h}{m _e c}$ is called compton wavelength.

The compton wavelength shift depends on

  1. Wavelength of the incident photon

  2. Material of the scatterer

  3. Energy of the incident photon

  4. Scattering angle


Correct Option: D
Explanation:

$\lambda -\lambda ^{1}=\dfrac{h}{m _e c}\ (1+cos  \theta )$
where $\theta$ is scattering angle.

So, the answer is option (D).

Given $h = 6.62 \times 10^{-34}$ Js, $m _e$ $= 9.1 \times 10^{-31}$ kg, $c = 3 \times 10^{8}$ m/s, the value of Compton wavelength is:

  1. 0.0121 $A^{0}$

  2. 0.0484 $A^{0}$

  3. 0.0242 $A^{0}$

  4. 0.0363 $A^{0}$


Correct Option: C
Explanation:

Compton wavelength $= \ \dfrac{h}{m _{e}c}$

$= \ \dfrac{6.62\times 10^{-34}}{9.1\times 10^{-31}\times 3\times 10^{8}}$

$= \ 0.242\times 10^{-11}m$

$= \ 0.0242\times 10^{-10}m$

$= \ 0.0242\ A^{\circ}$

In Compton scattering process, the incident X-radiation is scattered at an angle $60^o$. The wavelength of the scattered radiation is $0.22 A^o$. The wavelength of the incident X-radiation in $A^o$

  1. 0.508

  2. 0.408

  3. 0.232

  4. 0.208


Correct Option: D
Explanation:

By compton formula
$\Delta \lambda = \lambda _{f} -\lambda _{i}= \dfrac{h}{m _{e}C}(1-cos\theta )$

$0.22\ A^{\circ}-\lambda \ _{i}= 0.024A^{\circ}(1-\dfrac{1}{2}) \ \ \ \ (\because  cos60^{\circ}= 1/2)$

$\lambda   _{i}= 0.22-0.012$
$= 0.208  A^{\circ}$

So, the answer is option (D).

If the scattering angle of the photon in Compton effect is $180^{0}$, the Compton shift is

  1. Equal to the Compton wavelength of the electron

  2. four times the Compton wavelength of the electron

  3. two times the Compton wavelength of the electron

  4. half the compton wavelength of the electron


Correct Option: C
Explanation:

$\lambda -\lambda ^{1}  =  \dfrac{h}{m _e c}(1-cos  \theta )$

where
$\lambda $ is initial wavelength
$\lambda^{1} $ is the wavelength after & scattering
$h$ is the plank constant
$m _e$ is the electron rest mass.
$c$ is the speed of light
$\theta $ is the scattering angle.

Consider the following statements A and B, identify the correct choice in the given answers. 

A) Tightly bound electrons of target material scatter X-ray photon,resulting in the Compton effect. 
B) Photoelectric effect takes place with free electrons.

  1. Both A and B are true

  2. A is true but B is false

  3. A is false but B is true

  4. Both A and B are false


Correct Option: D
Explanation:

Compton effect happens with free electrons.
Photoelectric effect happens to bounded electrons.