CBSE Questions for Class 12 Medical Physics Magnetism And Matter Quiz 3 - MCQExams.com

A freely suspended magnetic needle will always come to rest in which direction ?
  • north-east direction
  • north-west direction
  • north-south direction
  • south-west direction
Which of the following statements given below is not true in the context of magnetic lines of force ?
  • Magnetic lines of forces are closed continuous curves
  • No two magnetic lines of force can intersect each other
  • Magnetic lines of force are close to each other at the poles
  • They start from the north pole and end on the south pole
Let $$r$$ be the distance of a point on the axis of a bar magnet from its centre. The magnetic field at such a point is proportional to :
  • $$\cfrac{1}{r}$$
  • $$\cfrac{1}{{r}^{2}}$$
  • $$\cfrac{1}{{r}^{3}}$$
  • none of these
The magnetic susceptibilty for diamagnetic materials is
  • small and negative
  • small and positive
  • large and positive
  • large and negative
Metals getting magnetised by orientation of atomic magnetic moments in external magnetic field are called
  • diamagnetics
  • paramagnetics
  • ferromagnetics
  • antimagnetics
Which of the following instruments is used to measure magnetic field?
  • Thermometer
  • Pyrometer
  • Hygrometer
  • Flux meter
Susceptibility is positive and large for a
  • paramagnetic substance
  • ferromagntic substance
  • diamagnetic substance
  • non magnetic substance
The magnetic lines of force inside a bar magnet:
  • From N-pole to S-pole of magent
  • Do not exist
  • Depend upon the area of cross section of bar magnet
  • From S-pole to N-pole of magnet
The meniscus of a liquid contained in one of the limbs of a narrow U-tube is held electromagnet with the meniscus in line with the field. The liquid is seen to rise. This indicates that the liquid is
  • anti-ferromagnetic
  • paramagnetic
  • diamagnetic
  • non-magnetic
The hysterisis curve is studied generally for 
  • ferromagnetic materials
  • paramagnetic materials
  • diamagnetic materials
  • All of the above
Of dia, para and ferromagnetism, the universal property of all substance is
  • diamagnetism
  • paramagnetism
  • ferromagnetism
  • all of the above
The narrowest hysterisis loop is for
  • cobalt steel
  • almico
  • soft magnetic material
  • stainless steel
In a cassette player, material used for coating magnetic tapes is :
  • cobalt
  • $$Co{Fe}_{2}{O}_{4}$$
  • $$Ni{Fe}_{2}{O}_{4}$$
  • nickel
Th direction of magnetic lines of force of a bar magnet is:
  • from south to north pole
  • from north to south pole
  • across the bar magnet
  • from south to north pole inside the magnet and from north to south pole outside the magnet
Among which the magnetic susceptibility does not depend on the temperature?
  • Dia-magnetism
  • Para-magnetism
  • Ferro-magnetism
  • Ferrite
Which magnetic materials have negative susceptibility?
  • Diamganetic materials
  • Paramagnetic materials
  • Ferromagnetic materials
  • All of the above
If a diamagnetic substance is brought near north and south pole of a bar magnet, it is
  • attracted by poles
  • repelled by poles
  • replaced by north pole and attracted by south pole
  • attracted by north pole and repelled by south pole
A ferromagnetic material is heated above its curie temperature. Which one of a correct statement?
  • Ferromagneitc domains are perfectly arranged
  • Ferromagnetic domains become random
  • Ferromagnetic domains are not influenced
  • Ferromagnetic material changes into diamagnetic material
Hysterisis is the phenomenon of lagging of
  • $$I$$ behind $$B$$
  • $$B$$ behind $$I$$
  • $$I$$ and $$B$$ behind $$H$$
  • $$H$$ behind $$I$$
Two isolated point poles of strength $$30Am$$ and $$60Am$$ are placed at a distance of $$0.3m$$. The force of repulsion is:
  • $$2\times { 10 }^{ -3 }N$$
  • $$2\times { 10 }^{ -4 }N$$
  • $$2\times { 10 }^{ 5 }N$$
  • $$2\times { 10 }^{ -5 }N$$
What conclusion is drawn regarding the magnetic field at a point if a compass needle at that point rests in any direction?
  • Magnetic field is non zero.
  • Magnetic field is zero.
  • Magnetic field is more than zero.
  • Magnetic field is less than zero.
How are the field lines in a uniform magnetic field ?
  • curved
  • parallel equidistant straight lines
  • parallel but non-equispaced straight lines
  • nothing can be said.
If the field lines in a magnetic field are parallel and equidistant, the magnetic field is __________ .
  • $$uniform$$
  • $$non\ uniform$$
  • $$zero$$
  • can not be determined
Curie temperature is the temperature above which
  • a ferromagnetic material becomes paramagnetic
  • a paramagnetic material becomes diamagnetic
  • a ferromagnetic material becomes diamagnetic
  • a paramagnetic material becomes ferromagnetic
If a magnetic substance is kept in a magnetic field then which of the following substance is thrown out?
  • Paramagnetic
  • Ferromagnetic
  • Diamagnetic
  • Antiferromagnetic
Which of the following is diamagnetism?
  • Aluminium
  • Quartz
  • Nickel
  • Bismuth
Figure shows the magnetic field lines in a magnetic field. A, B. and C are three points in this field. At what point is the magnetic field strong ?
205094_d1507e9ab4104bf2a4751002cfaa1c7a.png
  • A
  • B
  • C
  • All the above
A diamagnetic material in a magnetic field moves
  • perpendicular to field
  • from stronger to weaker parts of the field
  • from weaker to stronger parts of field
  • None of these
For which of the following substances, the magnetic susceptibility is independent of temperature?
  • diamagnetics only
  • paramagnetics only
  • ferromagnetics only
  • diamagnetics and paramagnetics both
A frog can jump higher than normal in a magnetic field because the tissues of a frog are
  • paramagnetic
  • diamagnetic
  • ferromagnetic
  • antiferro magnetic
Iron is ferromagnetic :
  • at all temperatures
  • at NTP only
  • above $${770}^{o}C$$
  • below $${770}^{o}C$$
In the hysteresis cycle, the value of $$H$$ needed to make the intensity of magnetism zero is called
  • Retentivity
  • Coercive force
  • Lorentz force
  • None of the above
A watch glass containing some powdered substance is placed between the pole pieces of a magnet. Deep concavity is observed at the centre. The substance in the watch glass is
  • iron
  • chromium
  • carbon
  • wood
A superconductor exhibits perfect:
  • ferrimagnetism
  • ferromagnetis
  • paramagnetism
  • diamagnetism
Magnetic force required to demagnetize the material
  • retainity
  • coercivity
  • energy loss
  • hysteresis
The magnetic materials having negative magnetic susceptibility are
  • non-magnetic
  • para magnetic
  • dia magnetic
  • ferro magnetic
The B-H curve (i) and (ii) shown in fig., associated with
205325_e93cf9c96d714e08ab9432ae84d07376.png
  • (i) diamagnetic and (ii) paramagnetic substance
  • (i) paramagnetic and (ii) ferromagnetic substance
  • (i) soft iron and (ii) steel respectively
  • (i) steel and (ii) soft iron respectively
A curve between magnetic moment and temperature of magnet is :
The force which makes magnet move
  • gravitational field
  • magnetic field
  • nuclear forces
  • air drag
Which of the following statements is wrong ? Magnetic lines of force
  • Form closed circuits
  • Never intersect
  • Are densest near the poles
  • None of the above
Identify the correct statement about the magnetic field lines
  • These start from the N-pole and terminate on the S-pole
  • These lines always form closed loops
  • Both (a) and (b) are correct
  • Both (a) and (b) are wrong
Diamagnetic material in a magnetic field moves
  • from stronger to the weaker parts of the field
  • from weaker to the stronger parts of the field
  • perpendicular to the field
  • in none of the above directions
Choose the correct statement about the properties of magnetic lines of forces.
  • Lines of force are not imaginary lines
  • Lines of force cannot be mapped on paper
  • Lines of force do not intersect each other
  • Lines of force always intersect each other
The value of resistivity of super conductor is 
  • zero
  • unity
  • infinity
  • none of these
Which metal is used to make ferromagnets ?
  • Iron
  • Cobalt
  • Nickel
  • All of these
Curie temperature is the temperature above which
  • Paramagnetic material becomes ferromagnetic material
  • Ferromagnetic material becomes diamgnetic material
  • Ferromagnetic material becomes paramagnetic material
  • Paramagnetic material becomes diamagnetic material
The universal property amongst all substances is 
  • diamgnetism
  • paramagnetism
  • ferromagnetism
  • non-magnetism
For protecting a sensitive equipment from external magnetic field, it should be
  • placed inside an iron can
  • placed inside an aluminium can
  • surrounded with fine copper sheet
  • wrapped with insulation around it when passing current through it
Magnetic lines of force determines :
  • The shape of the magnetic field
  • Only the direction of the magnetic field
  • Only the relative strength of the magnetic field
  • Both the direction and the relative strength ofthe magnetic field
The material suitable for making electromagnets should have
  • High retentivity and high coercivity
  • Low retentivity and low coercivity
  • High retentivity and low coercivity
  • Low retentivity and high coercivity
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