Manufacturing Engineering Multiple Choice Questions on “Magnetic Properties of Material”.
1. Which of the following parameter is used to assess the magnetic ability of a material?
a) Magnetic flux density
b) Magnetization
c) Magnetic dipole moment
d) Susceptibility
Answer: d
Clarification: Magnetic susceptibility is a measure to quantify the ability of a material to undergo magnetization in an applied magnetic field. It is the ratio of magnetization (M) to the applied magnetic field intensity (H).
2. For a diamagnetic material, which of the following statement is correct?
a) Magnetic susceptibility < 0
b) Magnetic susceptibility > 0
c) Magnetic susceptibility = 0
d) Magnetic susceptibility = 1
Answer: a
Clarification: Diamagnetic materials are those which repel magnetic field and hence their magnetic susceptibility (χ) is negative.
3. For a diamagnetic material, which of the following statement is correct (μr = relative permeability)?
a) μr > 2
b) μr < 1
c) μr > 1
d) μr = 1
Answer: b
Clarification: A diamagnetic material has a constant relative permeability (μr) slightly less than 1.
4. For a paramagnetic material, which of the following statement is correct?
a) Magnetic susceptibility < 0
b) Magnetic susceptibility > 0
c) Magnetic susceptibility = 0
d) Magnetic susceptibility = -1
Answer: b
Clarification: Magnetic susceptibility (χ) is very small positive quantity for a paramagnetic material.
5. For a paramagnetic material, which of the following statement is correct (μr = relative permeability)?
a) μr = 0
b) μr < 1
c) μr > 1
d) μr < 0
Answer: c
Clarification: A paramagnetic material has a constant relative permeability (μr) slightly greater than 1.
6. What is the curie temperature of iron (in kelvin scale)?
a) 2195 K
b) 495 K
c) 895 K
d) 1095 K
Answer: d
Clarification: The curie temperature of iron is about 1095K. It changes its magnetic behaviour from ferromagnetic to paramagnetic.
7. With an increase in temperature, magnetic susceptibility of a ferromagnetic material ____________
a) Increases
b) Decreases
c) Remains constant
d) First increases and then decreases
Answer: a
Clarification: Magnetic susceptibility of a ferromagnetic material decreases with increase in temeprature.
8. With an increase in temperature, magnetic susceptibility of an anti-ferromagnetic material ____________
a) Increases
b) Decreases
c) First decreases and then increases
d) First increases and then decreases
Answer: d
Clarification: Susceptibility of an anti-ferromagnetic material is first increases and then decreases with increase in temperature.
9. With an increase in the area of hysteresis curve, power loss will ___________
a) Increases
b) Decreases
c) First decreases and then increases
d) First increases and then decreases
Answer: a
Clarification: Power loss is directly proportional to the area of hysteresis curve.
10. Magnetic Bubbles are used as __________
a) Storage device
b) Strain gauge
c) Thermostat
d) Potentiometer
Answer: a
Clarification: Magnetic bubbles are small magnetized areas used as storage devices (data bites). One good thing about magnetic bubbles are they do not disappear when power is turned off.