The magnet of a vibration magnetometer is heated so as to reduce its magnetic moment by 19%. By doing this the periodic time of the magnetometer will

1. Increase by 19%       2. Decrease by 19%

3. Increase by 11%       4. Decrease by 21%

Concept Questions :-

Bar magnet
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A thin rectangular magnet suspended freely has a period of oscillation equal to T. Now it is broken into two equal halves (each having half of the original length) and one piece is made to oscillate freely in the same field. If its period of oscillation is T', then ratio T'/T is

1. 1/4

2. $1}{2\sqrt{2}}$

3. 1/2

4. 2

Concept Questions :-

Bar magnet
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

Two identical short bar magnets, each having magnetic moment M, are placed a distance of 2d apart with axes perpendicular to each other in a horizontal plane. The magnetic induction at a point midway between them is

(a)                  (b)

(c)  $\left(\frac{2{\mu }_{0}}{4\mathrm{\pi }}\right)\frac{M}{{d}^{3}}$                 (d)

Concept Questions :-

Bar magnet
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A magnet oscillating in a horizontal plane has a time period of 2 second at a place where the angle of dip is 30o and 3 seconds at another place where the angle of dip is 60o. The ratio of resultant magnetic fields at the two places is

(a) $\frac{4\sqrt{3}}{7}$                         (b) $\frac{4}{9\sqrt{3}}$

(c) $\frac{9}{4\sqrt{3}}$                         (d) $\frac{9}{\sqrt{3}}$

Concept Questions :-

Earth's magnetism
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Difficulty Level:

If the angular momentum of an electron is $\stackrel{\to }{J}$ then the magnitude of the magnetic moment will be

1. $\frac{eJ}{m}$                            2. $\frac{eJ}{2m}$

3. ej.2m                         4. $\frac{2m}{eJ}$

High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

The basic magnetization curve for a ferromagnetic material is shown in the figure. Then, the value of relative permeability is highest for the point : (a) P         (b) Q
(c) R         (d) S

Concept Questions :-

Magnetization and magnetic intensity
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Difficulty Level:

A superconductor exhibits perfect :
(a) Ferrimagnetism               (b) Ferromagnetism
(c) Paramagnetism               (d) Diamagnetism

Concept Questions :-

Magnetic materials

Difficulty Level:

Among the following properties describing diamagnetism identify  the property that is wrongly stated

1. Diamagnetic material do not have permanent magnetic moment

2. Diamagnetism is explained in terms of electromagnetic induction

3. Diamagnetic materials have a small positive susceptibility

4. The magnetic moment of individual electrons neutralize each other

Concept Questions :-

Magnetic materials
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

If a magnet is suspended at an angle 30o to the magnetic meridian, it makes an angle of 45o with the horizontal. The real dip is

(a)${\mathrm{tan}}^{-1}\left(\frac{\sqrt{3}}{2}\right)$

(b)${\mathrm{tan}}^{-1}\left(\sqrt{3}\right)$

(c)${\mathrm{tan}}^{-1}\left(\sqrt{\frac{3}{2}}\right)$

(d)${\mathrm{tan}}^{-1}\left(\frac{2}{\sqrt{3}}\right)$

Concept Questions :-

Earth's magnetism
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Difficulty Level:

The true value of angle of dip at a place is 60o, the apparent dip in a plane inclined at an angle of 30o with magnetic meridian is

(a)${\mathrm{tan}}^{-1}\left(\frac{1}{2}\right)$

(b)${\mathrm{tan}}^{-1}\left(2\right)$

(c)${\mathrm{tan}}^{-1}\left(\frac{2}{3}\right)$

(d)None of these

Concept Questions :-

Earth's magnetism