Tag: physics

Questions Related to physics

The inherent property of all materials is

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

  1. Diamagnetism

  2. Paramagnetism

  3. Ferromagnetism

  4. Both a and b

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Correct Option: A
Explanation:

Diamagnetism (where orbital motion of electrons creates tiny atomic current loops, which produce magnetic fields) is a property of all materials and opposes applied magnetic fields, but is very weak.

A thin diamagnetic rod is placed vertically between the poles of an electromagnet. When the current in the electromagnet is switched on, then the diamagnetic rod is pushed up, out of the horizontal magnetic field. Hence the rod gains gravitational potential energy. The work required to do this comes from.

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

  1. The lattice structure of the material of the rod

  2. The current source

  3. The induced electric field due to the changing magnetic field

  4. The magnetic field

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Correct Option: B
Explanation:

Here when electromagnet is connected to battery, emf source the magnetic field is produced which pushes rod upwards and so gravitational potential energy is stored.

This stored energy will require work which will come from current source or battery which is connected to electromagnet.
So option 2 is correct answer

A paramagnet magnet behaves like a solenoid because both contain currents in the form of

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

  1. Circles

  2. Parabola

  3. Straight line

  4. Ellipse

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Correct Option: A
Explanation:

A paramagnet magnet behaves like a solenoid because both contain currents in the form of circle. The magnetic field is generated by the circular motion of the electron inside the atom.

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

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

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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 $\epsilon _r >1$