Atomic diffusion MCQs : Here you will find MCQ Questions related to "Atomic diffusion" in Phase Transformation. These Atomic diffusion MCQ Questions Will help you to improve your Phase Transformation knowledge and will prepare you for various Examinations like Competitive Exams, Placements, Interviews and other Entrance Exmaniations.
Which of the following is a diffusion process whereby the random thermally-activated movement of atoms in a solid results in the net transport of atoms.
A. Atomic diffusion
B. interstitial diffusions
C. substitutional diffusions
D. interstitial and substitutional diffusions
Explanation: Atomic diffusion is a diffusion process whereby the random thermally-activated movement of atoms in a solid results in the net transport of atoms.
oxygen, nitrogen have ________ mobilities.
C. Can be A and B
D. Depends on state
Explanation: air molecules oxygen, nitrogen have lower mobilities and thus diffuse more slowly through the balloon wall
Which of the following atoms use the vacancy mechanism to diffuse?
A. Large atoms
B. Surface atoms
C. Substitutional atoms
D. Small interstitial atoms
Explanation: Substitutional atoms usually diffuse by a vacancy mechanism whereas the smaller interstitial atoms migrate by forcing their way between the larger atoms.
Assume that on average an interstitial B-atom jumps 10 times per second. The distance between the plane is given by 2m. Then, calculate the coefficient of diffusion of B atoms? (In m^2/s)
Explanation: For this question one can use the formula, Diffusion coefficient = 1/6*(number of times atom jumps) *(square of the distance between the plane) and just substitute the values in this formula we get the coefficient of diffusion as 20/3.
The rate of transport is governed by the diffusivity and the concentration gradient.
C. Can be true or false
D. Can not say
Explanation: True, The rate of transport is governed by the diffusivity and the concentration gradient.
In the crystal solid state, diffusion within the crystal lattice occurs by?
C. Both A and B
D. None of the above
Explanation: In the crystal solid state, diffusion within the crystal lattice occurs by either interstitial or substitutional mechanisms and is referred to as lattice diffusion.
What is the number of nearest neighbours present in FCC metals?
Explanation: The coordination number gives the total number of nearest neighbors for a lattice, here in FCC the coordination number is 12 hence the total number of nearest neighbors present in a FCC metal is 12.
Correlation factor in interstitial diffusion is _____
Explanation: Correlation factor in interstitial diffusion is 1, since we consider that the concentration of interstitial atoms is very low to make random jump possible because of availability of free sites to jump.
Which of the following is known as self-diffusion?
A. simple diffusion
B. facilitated diffusion.
C. interstitial lattice diffusion
D. substitutional lattice diffusion
Explanation: substitutional lattice diffusion known as self-diffusion
For a single atom in a defect-free crystal, the movement can be described by the "random walk" model.
C. Can be yes or no
D. Can not say
Explanation: Yes, For a single atom in a defect-free crystal, the movement can be described by the "random walk" model