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CBSE Questions for Class 12 Medical Physics Magnetism And Matter Quiz 10 - MCQExams.com

What is the phenomenon shown by ferromagnetic substances whereby the magnetic flux through the medium on magnetising field as well as previous state of the substance?
  • Irradiation
  • Hysteresis
  • Inversion
  • Magnetostriction
A substance is placed in a non uniform magnetic field. It experiences weak force towards the strong field. The substance is _________ type.
  • Ferromagnetic
  • Diamagnetic
  • Paramagnetic
  • None of these
Dynamo is a device that converts.
  • Alternating current into direct current
  • Electrical energy into mechanical energy
  • Mechanical energy into electrical energy
  • Heat energy into electrical energy
What is not true about paramagnetic substances?
  • When freely suspended in a uniform magnetic field, they align themselves parallel to the magnetic field
  • The magnetic susceptibility of paramagnetic substances has a small negative value
  • Para-magnetism is temperature dependent
  • They are feebly attracted by a magnet
Two equations are given below:
(A) ¯E.d¯A=Q0; (B) ¯B.d¯A=0
They are
  • (A)-Ampere's law; (B)- Guass law for electricity
  • (A)- Gauss law for electric fields; (B)- Gauss law for magnetic fields
  • (A)- Faraday law; (B)- Gauss law for electric fields
  • Both (A) and (B) represent Faraday law
The primary origin of magnetism lies in the
  • atomic current and intrinsic spin of electrons.
  • polar and non polar nature of molecules.
  • pauli exclusion principle.
  • electronegative nature of materials
If BE represents equatorial magnetic field and BA represents axial magnetic field due to a bar magnet. Which of the following relationships between BE and BA is correct?
  • BE=2BA
  • BA=2BE
  • BE=4BA
  • BA=4BE
If you made a map of magnetic field lines at Melbourne in Australia, then the magnetic field lines seem to be
  • go into the ground
  • come out of the ground
  • maintain a spiral path on the surface of earth
  • move on helical path above the surface of ground
The equatorial magnetic field of earth is 0.4G. Then its dipole moment on equator is
  • 1.05×1023Am2
  • 2.05×1023Am2
  • 1.05×1021Am2
  • 2.05×1021Am2
Which of the following is correct about magnetic monopole?
  • Magnetic monopole exist
  • Magnetic monopole does not exist
  • Magnetic monopole have constant value of monopole momentum
  • The monopole momentum increase due to increase at its distance from the field.
A ball of superconducting material is dipped in liquid nitrogen and placed near a bar magnet. In which direction will it move then?
  • Away from bar magnet
  • Towards the bar magnet
  • Around the bar magnet
  • Remains constant.
The strength of the earth's magnetic field is
  • constant everywhere
  • zero everywhere
  • having very high value
  • vary from place to place on the earths surface
The earth's field departs from its dipole shape substantially at large distance (greater than about 3000 km). The responsible factor for this distortion is then
  • motion of ions in earth's ionosphere
  • motion of ions in earth's atmosphere
  • motion of ions in earth's lithosphere
  • motion of ions in the space.
Which of the following is universal magnetic property.?
  • Ferromagnetism
  • Diamagnetism
  • Paramagnetism
  • Anti-ferromagnetism.
The correct M-H curve for a paramagnetic material at a constant temperature (T) is represented then by
Mark the correct set of ferromagnetic substances,
  • iron, cobalt and nickel
  • iron, copper and lead
  • silicon, bismuth and nickel
  • aluminium, sodium and copper.
The temperature of transition from ferromagnetic property to paramagnetic property is called as:
  • Transition temperature
  • Critical temperature
  • Curie temperature
  • Triplet temperature
Which of the following property shows the property of ferromagnetic substances?
  • The ferromagnetic property depends on temperature.
  • The ferromagnetic property does not depend on temperature.
  • At high enough temperature ferromagnet becomes a diamagnet
  • At low temperature ferromagnet becomes a paramagnet
Nickel shows ferromagnetic property at room temperature. If the temperature is increased beyond Curie temperature, then it will show the
  • anti ferromagnetism
  • no magnetic property
  • diamagnetism
  • paramagnetism
Out of given paramagnetic substance (Calcium, Chromium, Oxygen and Tungsten) which substance has maximum susceptibility?
  • Calcium
  • Chromium
  • Oxygen
  • Tungsten
A paramagnetic liquid is taken in a U-tube and arranged so that one of its limbs is kept between pole pieces of the magnet. The liquid level in the limb is
  • goes down
  • rises up
  • remains same
  • first goes down and then rise
Point out the wrong statement about the magnetic properties of soft iron and steel
  • Retentivity of soft iron is more than retentivity of steel.
  • Coercivity of soft iron is less than coercivity of steel.
  • Area of B-H loop in soft iron is smaller than the area of B-H loop for steel
  • Area of B-H loop in soft iron is greater than the area of B-H loop for steel
A domain in ferromagnetic iron is in the form of a cube of side length 2μ m then the number of iron atoms in the domain are (Molecular mass of iron = 55gmol1 and density = 7.92gcm3), maximum value of magnetisation of the given domain is (Dipole moment of an iton atom 9.27×1024Am2)
  • 8.0×105Am1
  • 6.0×104Am1
  • 8.0×103Am1
  • 6.0×103Am1
The magnetic susceptibility of a paramagnetic material at 730 is 0.0075, its value at 1730C will be
  • 0.0045
  • 0.0030
  • 0.015
  • 0.0075
Assertion : Paramagnetic substances get weakly attracted to a magnet.
Reason : They have tendency to move from a region of strong magnetic field to weak magnetic field
  • If both assertion and reason are true and reason is the correct explanation of assertion.
  • If both assertion and reason are true and reason is not the correct explanation of assertion.
  • If assertion is true but reason is false.
  • If both assertion and reason are false
Permanent magnets are the substances having the property of
  • ferromagnetism at room temperature for a long period of time.
  • paramagnetism at room temperature for a long period of time.
  • antiferromagnetism at room temperature for a long period of time.
  • diamagnetism at room temperature for a long period of time.
The hysteresis cycle for the material of a transformer core is:
  • short and wide
  • tall and narrow.
  • tall and wide
  • short and narrow
Identify the mismatched pair.
  • Hard magnet - Alnico
  • Soft magnet - Soft iron
  • Bar magnet - permanent magnet
  • Electromagnet - Loud speaker
Core of electromagnets are made of ferromagnetic material which have
  • low permeability and low retentivity
  • high permeability and high retentivity
  • high permeability and low retentivity
  • low permeability and high retentivity
Some equipotential surfaces of the magnetic scalar potential are shown in figure.Magnetic field at a point in the region is

943205_440663babd3d45eea8877e317baef5b1.png
  • 104 T
  • 0.5×104 T
  • 2×104 T
  • None of these
The earth's magnetic field lines resemble that of a dipole at the centre of the earth. if the magnetic moment of this dipole is close to 8×1022 Am2, the value of earth's magnetic field near the equator is close to (radius of the earth =6.4×106 m )
  • 0.6 Gauss
  • 1.2 Gauss
  • 1.8 Gauss
  • 0.32 Gauss
Assertion : When diamagnetic material is placed in a non-uniform magnetic field, it tends to move from stronger to the weaker part of the magnetic field.
Reason : Diamagnetic materials possess strong magnetism.
  • If both assertion and reason are true and reason is the correct explanation of assertion.
  • If both assertion and reason are true and reason is not the correct explanation of assertion.
  • If assertion is true but reason is false.
  • If both assertion and reason are false.
Assertion : Gauss's law of magnetism is different from that for electrostatics.
Reason : Isolated magnetic poles are not known to exist.
  • If both assertion and reason are true and reason is the correct explanation of assertion.
  • If both assertion and reason are true and reason is not the correct explanation of assertion.
  • If assertion is true but reason is false.
  • If both assertion and reason are false.
Assertion : In water, value of magnetic field decreases.
Reason : Water is a diamagnetic substance.
  • If both assertion and reason are true and reason is the correct explanation of assertion.
  • If both assertion and reason are true and reason is not the correct explanation of assertion.
  • If assertion is true but reason is false.
  • If both assertion and reason are false.
Assertion : When a bar magnet is freely suspended it points in the north - south direction.
Reason : The earth behaves as a magnet with the magnetic field pointing approximately from the geographic south to north
  • If both assertion and reason are true and reason is the correct explanation of assertion.
  • If both assertion and reason are true and reason is not the correct explanation of assertion.
  • If assertion is true but reason is false.
  • If both assertion and reason are false
If a magnetic material is having magnetic susceptibility (χ)=1, then the relative magnetic permeability (μr) and type of magnetic material is?
  • 0, diamagnetic
  • 2, ferromagnetic
  • 1, paramagnetic
  • 1, diamagnetic
Assertion : Substances which at room temperature retain their ferromagnetic property for a long period of time are called permanent magnets.
Reason : Permanent magnet can be made by placing a ferromagnetic rod in a solenoid and passing current through it.
  • If both assertion and reason are true and reason is the correct explanation of assertion.
  • If both assertion and reason are true and reason is not the correct explanation of assertion.
  • If assertion is true but reason is false.
  • If both assertion and reason are false.
Assertion : The product of magnetic susceptibility and absolute temperature for a paramagnetic substance is constant.
Reason : Susceptibility is positive but very small for paramagnetic substance.
  • If both assertion and reason are true and reason is the correct explanation of assertion.
  • If both assertion and reason are true and reason is not the correct explanation of assertion.
  • If assertion is true but reason is false.
  • If both assertion and reason are false
Assertion : At high temperature, a ferromagnet becomes a paramagnet.
Reason : The ferromagnetic property depends on temperature.
  • If both assertion and reason are true and reason is the correct explanation of assertion.
  • If both assertion and reason are true and reason is not the correct explanation of assertion.
  • If assertion is true but reason is false.
  • If both assertion and reason are false.
Which of the following is universal magnetic property?
  • Ferromagnetism
  • Diamagnetism
  • Para magnetism
  • Anti-ferromagnetism
A ball of superconducting material is dipped in liquid nitrogen and placed near a bar magnet. In which direction will it move?
  • Away from bar magnet
  • Towards the bar magnet
  • Around the bar magnet
  • Remain constant
Point out the correct set of diamagnetic substances.
  • Aluminium, sodium calcium and oxygen
  • Bismuth, copper, lead and silicon
  • Cobalt, nickel, gadolinium and aluminium
  • Silver, niobium, magnesium and calcium
Consider the two idealised systems.
(i) a parallel plate capacitor with large plates and small separation and
(ii) a long solenoid of length L >>R, radius of cross-section.
In (i) E is ideally treated as a constant between plates and zero outside. In (ii) magnetic field is constant inside the solenoid and zero outside. These idealised assumptions, however, contradict fundamental laws as given.
  • Case (i) contradicts Gauss's law for electrostatic fields
  • Case (ii) contradicts Gauss's law for magnetic fields
  • Case (i) agree with Edl=0
  • Case (ii) contradicts Hdl=Ien
Some equipotential surfaces of the magnetic scalar potential are shown in figure. Magnetic field at a point in the region is:
951075_e7bf29b9f21444098dcf7d4c264e63b2.png
  • 104T
  • 0.5×104T
  • 2×104T
  • None of these
Core of electromagnets are made of ferromagnetic materials which have.
  • Low permeability and low retentivity
  • High permeability and high retentivity
  • High permeability and low retentivity
  • Low permeability and high retentivity
In a permanent magnet at room temperature.
  • Magnetic moment of each molecule is zero
  • The individual molecules have non-zero magnetic moment which are all perfectly aligned
  • Domains are partially aligned
  • Domains are all perfectly aligned
Permanent magnets are the substances having the property of.
  • Ferromagnetism at room temperature for a long period of time
  • Paramagnetism at room temperature for a long period of time
  • Anti ferromagnetism at room temperature for a long period of time
  • Diamagnetism at room temperature for a long period of time
Mark the correct set of ferromagnetic substances.
  • Iron, cobalt and nickel
  • Iron, copper and lead
  • Silicon, bismuth and nickel
  • Aluminium, sodium and copper
Short Answer Type Question.
Which magnetic property is present in all substances?
  • Diamagnetism
  • massless
  • frictionless
  • no common property
In the region closer to the oscillating charges, the phase difference between E and B fields is _____ and their magnitude quickly decreases as _____ with distance r from the source.
  • 0,r1
  • π2,r1
  • π2,r3
  • 0,r3
0:0:2


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