Magnetism and Matter · Physics · NEET
MCQ (Single Correct Answer)
The magnetic potential energy, when a magnetic bar of magnetic moment $$\vec{m}$$ is placed perpendicular to the magnetic field $$\vec{B}$$ is
The incorrect relation for a diamagnetic material (all the symbols carry their usual meaning and $$\varepsilon$$ is a small positive number) is
The magnetic moment and moment of inertia of a magnetic needle as shown are, respectively, $$1.0 \times 10^{-2} \mathrm{~A} \mathrm{~m}^2$$ and $$\frac{10^{-6}}{\pi^2} \mathrm{~kg} \mathrm{~m}^2$$. If it completes 10 oscillations in $$10 \mathrm{~s}$$, the magnitude of the magnetic field is
The magnetic moment of an iron bar is $$M$$. It is now bent in such a way that it forms an arc section of a circle subtending an angle of $$60^{\circ}$$ at the centre. The magnetic moment of this arc section is
In a uniform magnetic field of $$0.049 \mathrm{~T}$$, a magnetic needle performs 20 complete oscillations in 5 seconds as shown. The moment of inertia of the needle is $$9.8 \times 10^{-6} \mathrm{~kg} \mathrm{~m}^2$$. If the magnitude of magnetic moment of the needle is $$x \times 10^{-5} \mathrm{~Am}^2$$, then the value of '$$x$$' is :
In the above diagram, a strong bar magnet is moving towards solenoid-2 from solenoid-1. The direction of induced current in solenoid-1 and that in solenoid-2, respectively, are through the directions:
Match List I with List II
| List I (Material) |
List II (Susceptibility ($$\chi)) |
||
|---|---|---|---|
| A. | Diamagnetic | I. | $$\chi=0$$ |
| B. | Ferromagnetic | II. | $$0 > \chi \ge -1$$ |
| C. | Paramagnetic | III. | $$\chi >> 1$$ |
| D. | Non-magnetic | IV. | $$0 < \chi < \varepsilon$$ (a small positive number) |
Choose the correct answer from the options given below.
A sheet is placed on a horizontal surface in front of a strong magnetic pole. A force is needed to:
A. hold the sheet there if it is magnetic.
B. hold the sheet there if it is non-magnetic.
C. move the sheet away from the pole with uniform velocity if it is conducting.
D. move the sheet away from the pole with uniform velocity if it is both, non-conducting and non-polar.
Choose the correct statement(s) from the options given below:
An iron bar of length $$L$$ has magnetic moment $$M$$. It is bent at the middle of its length such that the two arms make an angle $$60^{\circ}$$ with each other. The magnetic moment of this new magnet is :
The variation of susceptibility $$(\chi)$$ with absolute temperature ( $$\mathrm{T}$$ ) for a paramagnetic material is represented as :
A big circular coil of 1000 turns and average radius 10 m is rotating about its horizontal diameter at 2 rad s$$-$$1. If the vertical component of earth's magnetic field at that place is 2 $$\times$$ 10$$-$$5 T and electrical resistance of the coil is 12.56 $$\Omega$$, then the maximum induced current in the coil will be
$$\overrightarrow F = q\left( {\overrightarrow v \times \overrightarrow B } \right)$$
$$ = q\overrightarrow v \times \left( {B\widehat i + B\widehat j + {B_0}\widehat k} \right)$$
For q = 1 and $$\overrightarrow v = 2\widehat i + 4\widehat j + 6\widehat k$$ and $$\overrightarrow F = 4\widehat i - 20\widehat j + 12\widehat k$$
What will be the complete expression for $$\overrightarrow B $$ ?
(i) an equilateral tringle of side 'a'
(ii) A square of side 'a'
The magnetic dipole moments of the coil in each case respectively are :
$$\left( {{\mu _0} = 4\pi \times {{10}^{ - 7}}Tm{A^{ - 1}}} \right)$$
(i) A is feebly repelled
(ii) B is feebly attracted
(iii) C is strongly attracted
(iv) D remains unaffected
Which one of the following is true ?
The force on the charge Q is