Magnetic Properties - Properties and Applications of Materials - Engineering Sciences Previous Year Questions

1

2007 · Engineering Sciences · Properties and Applications of Materials · Magnetic Properties

Engineering Sciences (XE) 2007

Si is added to transformer grade steel to

A

decrease the magnetic permeability

B

decrease the electrical resistivity

C

improve the ductility

D

increase the magnetic permeability

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2

2007 · Engineering Sciences · Properties and Applications of Materials · Magnetic Properties

Engineering Sciences (XE) 2007

ZnFe2O4 has inverse spinel structure. Atomic numbers of Zn, Fe and O are 30, 26 and 8 respectively. The net magnetic moment of ZnFe2O4 per formula unit in terms of Bohr magneton (μB) will be

A

2 μB

B

1 μB

C

4 μB

D

0 μB

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3

2007 · Engineering Sciences · Properties and Applications of Materials · Magnetic Properties

Engineering Sciences (XE) 2007

Nb3Sn is widely used as current carrying element in fabrication of superconducting magnets since it

A

is a Type I superconductor

B

is a Type II superconductor and has large critical magnetic field

C

has Tc above boiling point of liquid helium (coolant used in superconducting magnets)

D

is an intermetallic

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4

2007 · Engineering Sciences · Properties and Applications of Materials · Magnetic Properties

Engineering Sciences (XE) 2007

A sine-wave voltage at 400 Hz feeds the transformer having 50 turns in the primary winding as shown in the figure. The transformer core material has a saturation flux density of 1.2 T and the hysteresis effects are neglected. The core area is 10 cm² and its relative permeability is 10⁵ till the core reaches saturation.
The maximum amplitude of the sine-wave that can be applied on the primary winding without causing saturation under steady state condition is

A

24 V

B

48 V

C

75.4 V

D

150.8 V

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5

2008 · Engineering Sciences · Properties and Applications of Materials · Magnetic Properties

Engineering Sciences (XE) 2008

A material in the superconducting state is

A

paramagnetic

B

diamagnetic

C

ferromagnetic

D

antiferromagnetic

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6

2008 · Engineering Sciences · Properties and Applications of Materials · Magnetic Properties

Engineering Sciences (XE) 2008

For a hard magnet, the remnant induction (B_r) is 0.5 Tesla and the coercive field (H_c) is 4×10⁵ A.m^-1. The energy loss of the magnet per cycle is

A

2 kJ.m^-3

B

20 kJ.m^-3

C

40 kJ.m^-3

D

80 kJ.m^-3

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7

2008 · Engineering Sciences · Properties and Applications of Materials · Magnetic Properties

Engineering Sciences (XE) 2008

The net magnetic moment of iron (Fe) is 2.22 \(\mu_B\) per atom. Calculate the saturation flux density in iron. (Density of iron : 7.87 g cm\(^{-3}\); Atomic mass of iron : 56 amu)

A

2.18×10\(^8\) Tesla

B

2.18×10\(^{-12}\) Tesla

C

2.18×10\(^0\) Tesla

D

2.18 Tesla

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8

2009 · Engineering Sciences · Properties and Applications of Materials · Magnetic Properties

Engineering Sciences (XE) 2009

Ferrites are preferred materials for use in high frequency applications (GHz range) as opposed to other ferromagnetic materials because ferrites also have

A

High permeability

B

High electrical resistivity

C

High saturation magnetisation

D

Low coercivity

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9

2009 · Engineering Sciences · Properties and Applications of Materials · Magnetic Properties

Engineering Sciences (XE) 2009

Match the following classes of materials given in Column I with the electron spin alignments in atoms shown in Column II.

A

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10

2010 · Engineering Sciences · Properties and Applications of Materials · Magnetic Properties

Engineering Sciences (XE) 2010

If the effective magnetic moment of Fe³⁺ is equal to 5 μ_B, the magnetic moment in μ_B per formula of γ-Fe₂O₃ (which is inverse spinel with cation defects on the octahedral site) is

A

zero

B

2.5

C

5

D

10

Check answer

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11

2010 · Engineering Sciences · Properties and Applications of Materials · Magnetic Properties

Engineering Sciences (XE) 2010

The upper critical field (B_C2) in Tesla is

A

0.10

B

0.33

C

1.00

D

10.00

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12

2010 · Engineering Sciences · Properties and Applications of Materials · Magnetic Properties

Engineering Sciences (XE) 2010

The maximum energy that can be stored per unit volume ( Jm^-3) in the superconductor is

A

3.979 × 10³

B

50.00 × 10³

C

7.96 × 10³

D

1.326 × 10³

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13

2011 · Engineering Sciences · Properties and Applications of Materials · Magnetic Properties

Engineering Sciences (XE) 2011

Nickel ferrite is

A

antiferromagnetic

B

ferromagnetic

C

diamagnetic

D

ferrimagnetic

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14

2012 · Engineering Sciences · Properties and Applications of Materials · Magnetic Properties

Engineering Sciences (XE) 2012

The best magnetostrictive material is

A

Nd₂Fe₁₄B

B

Fe₃O₄

C

Cu₂MnAl

D

ZnFe₂O₄

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15

2012 · Engineering Sciences · Properties and Applications of Materials · Magnetic Properties

Engineering Sciences (XE) 2012

Calculate the saturation magnetization (M_sat) for bcc iron of lattice parameter 2.866 Å.

A

0.79 × 10⁶ A/m

B

1.5 × 10⁶ A/m

C

3.15 × 10⁶ A/m

D

4.73 × 10⁶ A/m

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16

2014 · Engineering Sciences · Properties and Applications of Materials · Magnetic Properties

Engineering Sciences (XE) 2014

The temperature of the antiferromagnetic-to-paramagnetic transition is called

A

Curie temperature

B

Curie-Weiss temperature

C

Neel temperature

D

Debye temperature

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17

2015 · Engineering Sciences · Properties and Applications of Materials · Magnetic Properties

Engineering Sciences (XE) 2015

Which of the following is NOT a soft magnetic material?

A

Iron-silicon steel

B

Nickel zinc ferrite

C

Nickel iron alloy

D

Alnico

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18

2016 · Engineering Sciences · Properties and Applications of Materials · Magnetic Properties

Engineering Sciences (XE) 2016

Match the type of magnetism given in Group 1 with the material given in Group 2:

Group 1	Group 2
P: Ferromagnetic	1: Nickel oxide
Q: Ferrimagnetic	2: Sodium
R: Antiferromagnetic	3: Magnetite
S: Paramagnetic	4: Cobalt

A

P-4, Q-3, R-1, S-2

B

P-4, Q-1, R-3, S-2

C

P-1, Q-2, R-4, S-3

D

P-3, Q-2, R-1, S-4

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19

2017 · Engineering Sciences · Properties and Applications of Materials · Magnetic Properties

Engineering Sciences (XE) 2017

Which of the following statement(s) is / are true regarding susceptibility of a material (i) Magnetic susceptibility is positive for a diamagnetic material (ii) Magnetic susceptibility is negative for a diamagnetic material (iii) Magnetic susceptibility is negative for an antiferromagnetic material (iv) Magnetic susceptibility is positive for a paramagnetic material

A

(ii) and (iv)

B

(i) and (iii)

C

(ii) and (iii)

D

(i) and (iv)

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20

2018 · Engineering Sciences · Properties and Applications of Materials · Magnetic Properties

Engineering Sciences (XE) 2018

If a material is repelled in an external magnetic field then it is

A

Ferromagnetic

B

Diamagnetic

C

Paramagnetic

D

Antiferromagnetic

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