Engineering Questions with Answers - Multiple Choice Questions

# Materials Science MCQ’s – Influential Factors

1 - Question

On which of the following does diffusion not depend on?
a) Temperature
b) Pressure
c) Concentration difference
d) Diffusion distance
Explanation: Diffusion depends on the temperature, concentration difference as atoms diffuse from higher concentration region to lower concentration region, diffusion distance. It does not depend on pressure.

2 - Question

When something burns on the stove in the kitchen, the whole kitchen starts smelling smoky due to diffusion.
a) True
b) False
Explanation: When something burns on the stove, the atoms of the burnt food starts spreading in the kitchen by random atomic motion by the process of diffusion. The burnt food atoms start moving from places where their concentration is high to regions of low concentration.

3 - Question

If we increase the temperature, how is the diffusion rate affected?
a) Diffusion rate increases
b) Diffusion rate decreases
c) Diffusion rate decreases drastically
d) Diffusion rate is not affected
Explanation: As the temperature increases, the kinetic energy of particles increases and hence they start moving randomly faster. Due to the increase in energy the particles bounce again each other faster and start spreading evenly throughout the volume.

4 - Question

How is the diffusion rate affected by concentration difference?
a) Diffusion rate is not affected
b) Higher the concentration difference, higher the diffusion rate
c) Lower the concentration difference, higher the diffusion rate
d) Higher the concentration difference, lower the diffusion rate
Explanation: The particles tend to move from higher concentration region to lower concentration difference. Therefore, higher the concentration difference, higher is the rate of diffusion.

5 - Question

How is diffusion rate related to diffusion distance?
a) Directly related
b) Inversely related
c) Not related
d) Directly related to square of diffusion distance
Explanation: The diffusion rate is inversely proportional to the distance from which the particles are diffusing. Larger the diffusion distance, the rate of diffusion is slower and vice versa.

6 - Question

How is the rate of diffusion affected by the weight of diffusing atom?
a) Lighter atoms diffuse faster
b) Heavier atoms diffuse faster
c) Lighter atom diffuses slower
d) Rate of diffusion doesn’t depend on weight of diffusing atom
Explanation: At a given temperature, average energy of atoms is equal and hence the rate of diffusion will depend on the size and weight of the diffusing atom. A lighter atom will diffuse faster than a heavier atom.

7 - Question

Diffusion is slower for _________
a) Open crystal structure
b) Low density materials
c) Materials with lower melting temperature
d) Materials with covalent bonding