Tag: magnetic materials

Questions Related to magnetic materials

Domain formation is the necessary features of

physics magnetism and matter magnetic materials behaviour of substances in magnetic field classification of magnetic materials

  1. Diamagnetism

  2. Paramagnetism

  3. Ferromagnetism

  4. All of these

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Correct Option: C
Explanation:

Ferromagnetism materials exhibit a long range ordering phenomenon at the atomic level which causes the unpaired electron spins to line up parallel with each other in a region called domain. Within the domain, the magnetic field is intense, but in a bulk sample the material will usually be unmagnetised because the many domains will themselves be randomly oriented with respect to one another. Hence, domain formation is the necessary feature of ferromagnetic substance.

If a solution of ferromagnetic material is poured into a U-tube and one arm of this is placed between the poles of a strong magnet with the meniscus in line with the field, then the level of the solution will:

physics magnetism and matter magnetic materials behaviour of substances in magnetic field classification of magnetic materials

  1. Rise

  2. Fall

  3. Rise till the liquid comes out

  4. Remain unchanged

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Correct Option: A

The susceptibility of a diamagnetic material is

physics magnetism and matter magnetic materials behaviour of substances in magnetic field classification of magnetic materials

  1. directly proportional to $T$

  2. inversely proportional to $T $

  3. independent of $\mathrm { T } $

  4. inversely proportional to $\mathrm { T } ^ { 2 }$

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Correct Option: B

The value of magnetic susceptibility for para-magnetic substance is  

physics magnetism and matter magnetic materials behaviour of substances in magnetic field classification of magnetic materials

  1. infinity

  2. low positive

  3. low negative

  4. zero

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Correct Option: B
Explanation:

Paramagnetic substance gets feebly magnetised in the direction of field and therefore, $I$ is very small and positive for paramagntic substances.
We know $X _m=I/H$
Therefore,$X _m$ is also very small and positive.

Relative permittivity and permeability of a material are $\varepsilon _{r}$ and $\mu _{r}$ respectively. The values of these quantities allowed for a diamagnetic material are

physics magnetism and matter magnetic materials behaviour of substances in magnetic field classification of magnetic materials

  1. $\varepsilon _{r}=0.5,\mu _{r}=1.5$

  2. $\varepsilon _{r}=1.5,\mu _{r}=0.5$

  3. $\varepsilon _{r}=0.5,\mu _{r}=0.5$

  4. $\varepsilon _{r}=1.5,\mu _{r}=1.5$

Show answer
Correct Option: B
Explanation:

For diamagnetic material
$0\leq \mu _{r}< 1$
And for any material, $ \varepsilon _{r}> 1$

So, option B.

Magnetism is a property present in ___________.

physics magnetism and matter magnetic materials behaviour of substances in magnetic field classification of magnetic materials

  1. Only a few materials

  2. Only ferromagnetic material

  3. Only paramagnetic material

  4. All materials

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Correct Option: D
Explanation:

Magnetization is present in all materials. It is a class of physical phenomenon that is mediated by Magnetic fields.

The magnetic state of different materials depends on temperature and other variables such as pressure and applied magnetic field.

 

Relative permittivity and permeability of a material are $\epsilon _{\mathrm{r}}$ and $\mu _{\mathrm{r}}$, respectively. Which of the following values of these quantifies are allowed for a diamagnetic material? 

physics magnetism and matter magnetic materials behaviour of substances in magnetic field classification of magnetic materials

  1. $\epsilon _{\mathrm{r}}=0.5,\ \mu _{\mathrm{r}}=0.5$

  2. $\epsilon _{\mathrm{r}}=1.5,\ \mu _{\mathrm{r}}=1.5$

  3. $\epsilon _{\mathrm{r}}=0.5,\ \mu _{\mathrm{r}}=1.5$

  4. $\epsilon _{\mathrm{r}}=1.5,\ \mu _{\mathrm{r}}=0.5$

Show answer
Correct Option: D
Explanation:

For a diamagnetic material, $\mu _r$ and $\epsilon _r$ should have following bounds $0<\mu _r <1$ and for any material $\epsilon _r >1$

Needles $N _{1}, N _{2}$ and $N _{3}$ are made of a ferromagnetic, a paramagnetic and a diamagnetic substance respectively. A magnet when brought close to them will 

physics magnetism and matter magnetic materials behaviour of substances in magnetic field classification of magnetic materials

  1. attract all three of them.

  2. attract $\mathrm{N} _{1}$ and $\mathrm{N} _{2}$ strongly but repel $\mathrm{N} _{3}$. 

  3. attract $\mathrm{N} _{1}$ strongly, $\mathrm{N} _{2}$ weakly and repel $\mathrm{N} _{3}$ weakly.

  4. attract $\mathrm{N} _{1}$ strongly, but repel $\mathrm{N} _{2}$ and $\mathrm{N} _{3}$ weakly.

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Correct Option: C
Explanation:

Ferromagnetic substances are strongly attracted by a magnet while, paramagnetic and diamaganetic substances are weakly attracted and repelled respectively.

Curie temperature is the temperature above which 

physics magnetism and matter magnetic materials behaviour of substances in magnetic field classification of magnetic materials

  1. a ferromagnetic material becomes paramagnetic

  2. a paramagnetic material becomes diamagnetic

  3. a ferromagnetic material becomes diamagnetic

  4. a paramagnetic material becomes ferromagnetic.

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Correct Option: A
Explanation:

The Curie temperature is the temperature above which ferromagnetic materials lose their permanent magnetic field, the magnetism completely disappears. Above Curie temperature, the material behaves para-magnetically.

A ferromagnetic material is placed in an external magnetic field. The magnetic domains 

physics magnetism and matter magnetic materials behaviour of substances in magnetic field classification of magnetic materials

  1. Increase in size

  2. Decrease in size

  3. May increase or decrease is size

  4. Have no relation with the field

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Correct Option: A