CBSE Questions for Class 12 Medical Physics Magnetism And Matter Quiz 4 - MCQExams.com

When a bar magnet is broken into two pieces:
  • we will have a single pole on each piece
  • each piece will have two unlike poles
  • each piece will have two like poles
  • none of these
A small magnet is placed perpendicular to a uniform magnet field. The forces acting on the magnet will result in:
  • Rotational motion
  • Straight line motion
  • No motion at all
  • Both straight line and rotational motion 
Choose the correct statement
  • 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
Which of the following group is diamagnetic?
  • Copper, hydrogen, silver
  • Copper, hydrogen, argon
  • Hydrogen, oxygen, argon
  • Copper, silver, oxygen
Which of the following figures represents the magnetic lines of force due to an isolated north pole?
  • Both
  • None
Magnetic lines of force
  • are mere directions
  • have no physical reality
  • can be used to indicate the direction of the magnetic field at point
  • all the above are correct
The force which a magnet exerts on iron and steel is called the
  • electric force
  • magnetic force
  • nuclear force
  • gravitational force
The space surrounding a magnet within which the magnetic effect is felt is called
  • Magnetic field
  • Intensity of magnetic field
  • Magnetic meridian
  • None of these
Which of the following figures represents the magnetic lines of force due to an isolated south pole?
Among the following _____ has the highest retentivity.
  • aluminium
  • steel
  • nickel
  • soft iron
A diamagnetic substance produces a
  • Strong magnetic field in opposition of an externally applied magnetic field
  • Weak magnetic field in the direction of an externally applied magnetic field
  • Weak magnetic field in opposition of an externally applied magnetic field
  • Strong magnetic field in the direction of an externally applied magnetic field
When two magnetic poles having same pole strength are separated by a distance of $$20$$ $$cm$$, a force of $$5$$ $$N$$ acts between them. If the distance is halved, the force becomes ______
  • $$20$$ N
  • $$10$$ N
  • $$15$$ N
  • $$25$$ N
A magnetic field is said to be produced by a current-carrying conductor. The magnetic lines of force:
  • Are parallel to the length of the conductor.
  • Are perpendicular to the length of the conductor.
  • Form an acute angle with the length of the conductor.
  • Form an obtuse angle with the length of the conductor.
 P Q R
 MagnetsMagnetic SubstanceNon Magnetic Substance 
An object is repelled by a magnet. It must be placed in the group :
  • P
  • Q
  • R
  • Either P or Q
Which of the following is not a property of magnetic lines of force?
  • They neither have origin nor end.
  • These lines do not intersect.
  • Outside the magnet their direction is from north pole to south pole and inside the magnet these are from south to north pole.
  • None
Mark the incorrect statement.
  • Field line is the path along which a hypothetical free north pole would tend to move.
  • The direction of the magnetic field at a point is given by the direction that a north pole placed at that point would take.
  • Field lines are shown closer together where the magnetic field is greater.
  • None
_______ exists in the region surrounding a magnet, in which force of the magnet can be detected.
  • Electric field
  • Magnetic field
  • both
  • none
Properties of magnetic lines of force are:
  • The imaginary lines which represent the direction of magnetic field, are known as magnetic lines of force.
  • Magnetic lines of force are closed curves.
  • Outside the magnet their direction is from north pole to south pole and inside the magnet these are from south to north pole.
  • All
Field lines are shown close together where the
  • magnetic field is far apart
  • magnetic fields is zero
  • magnetic fields is greater
  • all
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
A magnetic field line is used to find the direction of:
  • south-north
  • a bar magnet
  • a compass needle
  • magnetic field
Among the following properties describing diamagnetism identify the property that is wrongly stated.
  • Diamagnetic material do not have permanent magnetic moment
  • Diamagnetism is explained in terms of electromagnetic induction
  • Diamagnetic materials have a small positive susceptibility
  • The magnetic moment of individual electrons neutralize each other
Which of the following best describes the field due to a magnet ?
  • The region where its effects are felt
  • The two regions close to its poles
  • The region between its poles
  • The region where it aligns itself along the north-south direction
On applying an external magnetic field, to a ferromagnetic substance domains.
  • Align in the direction of magnetic field.
  • Align in the direction opposite to magnetic field.
  • Remain unaffected
  • align randomly
Like magnetic force ______ each other.
  • repel
  • attract
  • strike
  • all
Who discovered the magnetic effect of electric current?
  • Oersted
  • Newton
  • Einstein
  • Maxwell
For diamagnetic materials, magnetic susceptibility is 
  • Small and negative
  • Small and positive
  • Large and negative
  • Large and positive
Space surrounding a magnet in which magnetic force is executed, is called a
  • electric field.
  • magnetic field
  • north field
  • all
Magnetic field can be defined as the:
  • space surrounding the  magnet in which magnetic force acts
  • space surrounding the magnet in which electric force acts
  • space surrounding the magnet in which no force acts
  • none
Nickel shows ferromagnetic property at room temperature. If the temperature is increased beyond Curie temperature, then it will show :
  • paramagnetism
  • anti-ferromagnetism
  • no magnetic property
  • diamagnetism
Meena draws magnetic field lines of the field close to the axis of a current carrying circular loop. As she moves away from the center of the circular loop she observes that the lines keep
  • on diverging.
  • on converging
  • diappearing
  • none
Which of the following best describe magnetic field line?
  • It represents the direction of the magnetic field
  • It represents the strength of the magnetic field
  • It represents the direction of the magnetic field force
  • It intersects other magnetic field lines
  • It points away from the south pole and toward the north pole
Curie-Weiss law is obeyed by iron :
  • at Curie temperature only.
  • at all temperatures.
  • below Curie temperature.
  • above Curie temperature.
A frog can be levitated in magnetic field produced by a current in a vertical solenoid placed below the frog. This is possible because the body of the frog behaves as
  • Paramagnetic
  • Diamagnetic
  • Ferromagnetic
  • Anti-ferromagnetic
Magnetically aligned atoms in a magnetic material forms a cluster. The cluster is called a:
  • Domain
  • Molecule
  • Pole
  • Charge
  • Electron cloud
Which of the following best describe the spacing of the field lines ?
  • Indicates the strength of the magnetic field
  • Is greatest near the poles
  • Is smallest far away from the poles
  • Indicates the direction of the magnetic field
  • Is the same everywhere around the magnet
The ________ drawn at any point on the magnetic lines of force gives direction of magnetic field at that point.
  • tangent
  • perpendicular
  • chord
  • None
State True or False.

Magnetic lines of force do not intersect.
  • True
  • False
To protect an instrument from external magnetic field, it is put inside an iron box.
  • True
  • False
A space or region around a magnet in which a force is experienced by magnetic pole is called.
  • Magnetic field
  • Magnetic force
  • Magnetic moment
  • Magnetic axis
An electromagnet:
  • has its own persistent magnetic field
  • acts as a magnet when an electric current passes through it
  • both A and B
  • none of the above
The most important features of superconductor is that
  • once current is set up in a superconductor ring, it will continue indefinitely even if the battery is off.
  • it has high efficiency compared to other conductors
  • it can pass maximum no of electrons when current is passed through it.
  • none of the above
Which of the following is the use of superconductor?
  • They are used in powerful electromagnets
  • They are used in microwaves
  • They are used in MRI
  • All of the above
The energy band gap of a superconductor formed near the critical temperature is due to 
  • the exponential decrease in heat capacity
  • the exponential increase in heat capacity
  • the gradually decrease in heat capacity
  • the gradually increase in heat capacity
Bell laboratory has developed superconductor at a temperature of 
  • 30 K
  • 40 K
  • 50 K
  • 60 K
The upper limit temperature of a super conductor is 
  • 115 K
  • 120 K
  • 125 K
  • 130 K
$${ \chi  }_{ 1 }$$ and $${ \chi  }_{ 2 }$$ are susceptibility of a paramagnetic material at temperatures $${T}_{1}K$$ and $${T}_{2}K$$ respectively, then
  • $${ \chi }_{ 1 }={ \chi }_{ 2 }$$
  • $${ \chi }_{ 1 }{ T }_{ 1 }={ \chi }_{ 2 }{ T }_{ 2 }$$
  • $${ \chi }_{ 1 }{ T }_{ 2 }={ \chi }_{ 2 }{ T }_{ 1 }$$
  • $${ \chi }_{ 1 }\sqrt { { T }_{ 1 } } ={ \chi }_{ 2 }\sqrt { { T }_{ 2 } } $$
The dependence of the critical temperature for superconductivity upon 
  • isotopic mass
  • isotonic mass
  • isobaric mass
  • Both A and B
The temperature bellow which a material becomes a superconductor is called 
  • critical temperature
  • absolute temperature
  • tripple point
  • none of the above
Core of electromagnets are made of ferromagnetic material which has:
  • High permeability and Low retentivity
  • High permeability and High retentivity
  • Low permeability and High retentivity
  • Low permeability and Low retentivity
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