Q.1.
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?
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Irradiation
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Hysteresis
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Inversion
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Magnetostriction
Q.2.
A substance is placed in a non uniform magnetic field. It experiences weak force towards the strong field. The substance is _________ type.
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Ferromagnetic
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Diamagnetic
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Paramagnetic
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None of these
Q.3.
Dynamo is a device that converts.
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Alternating current into direct current
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Electrical energy into mechanical energy
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Mechanical energy into electrical energy
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Heat energy into electrical energy
Q.4.
What is not true about paramagnetic substances?
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When freely suspended in a uniform magnetic field, they align themselves parallel to the magnetic field
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The magnetic susceptibility of paramagnetic substances has a small negative value
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Para-magnetism is temperature dependent
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They are feebly attracted by a magnet
Q.5.
Two equations are given below:
(A) $$\oint { \overline { E } .d\overline { A } =\cfrac { Q }{ { \in }_{ 0 } } } \quad $$; (B) $$\quad \oint { \overline { B } .d\overline { A } } =0$$
They are
(A) $$\oint { \overline { E } .d\overline { A } =\cfrac { Q }{ { \in }_{ 0 } } } \quad $$; (B) $$\quad \oint { \overline { B } .d\overline { A } } =0$$
They are
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(A)-Ampere's law; (B)- Guass law for electricity
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(A)- Gauss law for electric fields; (B)- Gauss law for magnetic fields
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(A)- Faraday law; (B)- Gauss law for electric fields
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Both (A) and (B) represent Faraday law
Q.6.
The primary origin of magnetism lies in the
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atomic current and intrinsic spin of electrons.
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polar and non polar nature of molecules.
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pauli exclusion principle.
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electronegative nature of materials
Q.7.
If $$B_E$$ represents equatorial magnetic field and $$B_A$$ represents axial magnetic field due to a bar magnet. Which of the following relationships between $$B_E$$ and $$B_A$$ is correct?
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$$B_E = 2 B_A$$
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$$B_A = 2 B_E$$
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$$B_E = 4 B_A$$
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$$B_A = 4 B_E$$
Q.8.
If you made a map of magnetic field lines at Melbourne in Australia, then the magnetic field lines seem to be
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go into the ground
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come out of the ground
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maintain a spiral path on the surface of earth
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move on helical path above the surface of ground
Q.9.
The equatorial magnetic field of earth is $$0.4$$G. Then its dipole moment on equator is
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$$1.05 \times 10^{23} A m^2$$
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$$2.05 \times 10^{23} A m^2$$
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$$1.05 \times 10^{21} A m^2$$
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$$2.05 \times 10^{21} A m^2$$
Q.10.
Which of the following is correct about magnetic monopole?
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Magnetic monopole exist
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Magnetic monopole does not exist
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Magnetic monopole have constant value of monopole momentum
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The monopole momentum increase due to increase at its distance from the field.
Q.11.
A ball of superconducting material is dipped in liquid nitrogen and placed near a bar magnet. In which direction will it move then?
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Away from bar magnet
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Towards the bar magnet
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Around the bar magnet
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Remains constant.
Q.12.
The strength of the earth's magnetic field is
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constant everywhere
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zero everywhere
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having very high value
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vary from place to place on the earths surface
Q.13.
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
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motion of ions in earth's ionosphere
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motion of ions in earth's atmosphere
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motion of ions in earth's lithosphere
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motion of ions in the space.
Q.14.
Which of the following is universal magnetic property.?
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Ferromagnetism
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Diamagnetism
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Paramagnetism
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Anti-ferromagnetism.
Q.15.
The correct M-H curve for a paramagnetic material at a constant temperature (T) is represented then by
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0%
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0%
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0%
Q.16.
Mark the correct set of ferromagnetic substances,
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iron, cobalt and nickel
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iron, copper and lead
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silicon, bismuth and nickel
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aluminium, sodium and copper.
Q.17.
The temperature of transition from ferromagnetic property to paramagnetic property is called as:
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Transition temperature
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Critical temperature
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Curie temperature
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Triplet temperature
Q.18.
Which of the following property shows the property of ferromagnetic substances?
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The ferromagnetic property depends on temperature.
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The ferromagnetic property does not depend on temperature.
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At high enough temperature ferromagnet becomes a diamagnet
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At low temperature ferromagnet becomes a paramagnet
Q.19.
Nickel shows ferromagnetic property at room temperature. If the temperature is increased beyond Curie temperature, then it will show the
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anti ferromagnetism
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no magnetic property
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diamagnetism
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paramagnetism
Q.20.
Out of given paramagnetic substance (Calcium, Chromium, Oxygen and Tungsten) which substance has maximum susceptibility?
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Calcium
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Chromium
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Oxygen
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Tungsten
Q.21.
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
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goes down
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rises up
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remains same
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first goes down and then rise
Q.22.
Point out the wrong statement about the magnetic properties of soft iron and steel
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Retentivity of soft iron is more than retentivity of steel.
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Coercivity of soft iron is less than coercivity of steel.
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Area of B-H loop in soft iron is smaller than the area of B-H loop for steel
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Area of B-H loop in soft iron is greater than the area of B-H loop for steel
Explanation
Q.23.
A domain in ferromagnetic iron is in the form of a cube of side length 2$$\mu $$ m then the number of iron atoms in the domain are (Molecular mass of iron = $$55 g mol^{-1}$$ and density = $$7.92 g cm^{-3}$$), maximum value of magnetisation of the given domain is (Dipole moment of an iton atom $$9.27 \times 10^{-24}A m^2)$$
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$$8.0 \times 10^5 A m^{-1}$$
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$$6.0 \times 10^4 A m^{-1}$$
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$$8.0 \times 10^3 A m^{-1}$$
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$$6.0 \times 10^3 A m^{-1}$$
Q.24.
The magnetic susceptibility of a paramagnetic material at $$-73^0$$ is $$0.0075$$, its value at $$-173^0$$C will be
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$$0.0045$$
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$$0.0030$$
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$$0.015$$
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$$0.0075$$
Q.25.
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
Reason : They have tendency to move from a region of strong magnetic field to weak magnetic field
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If both assertion and reason are true and reason is the correct explanation of assertion.
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If both assertion and reason are true and reason is not the correct explanation of assertion.
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If assertion is true but reason is false.
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If both assertion and reason are false
Q.26.
Permanent magnets are the substances having the property of
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ferromagnetism at room temperature for a long period of time.
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paramagnetism at room temperature for a long period of time.
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antiferromagnetism at room temperature for a long period of time.
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diamagnetism at room temperature for a long period of time.
Q.27.
The hysteresis cycle for the material of a transformer core is:
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short and wide
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tall and narrow.
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tall and wide
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short and narrow
Q.28.
Identify the mismatched pair.
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Hard magnet - Alnico
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Soft magnet - Soft iron
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Bar magnet - permanent magnet
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Electromagnet - Loud speaker
Q.29.
Core of electromagnets are made of ferromagnetic material which have
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low permeability and low retentivity
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high permeability and high retentivity
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high permeability and low retentivity
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low permeability and high retentivity
Q.30.
Some equipotential surfaces of the magnetic scalar potential are shown in figure.Magnetic field at a point in the region is
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$$10^{-4}$$ T
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$$0.5 \times 10^{-4}$$ T
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$$2 \times 10^{-4}$$ T
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None of these
Q.31.
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 $$8\times 10^{22}\ Am^{2}$$, the value of earth's magnetic field near the equator is close to (radius of the earth $$=6.4\times 10^{6}\ m$$ )
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$$0.6$$ Gauss
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$$1.2$$ Gauss
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$$1.8$$ Gauss
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$$0.32$$ Gauss
Q.32.
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.
Reason : Diamagnetic materials possess strong magnetism.
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If both assertion and reason are true and reason is the correct explanation of assertion.
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If both assertion and reason are true and reason is not the correct explanation of assertion.
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If assertion is true but reason is false.
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If both assertion and reason are false.
Q.33.
Assertion : Gauss's law of magnetism is different from that for electrostatics.
Reason : Isolated magnetic poles are not known to exist.
Reason : Isolated magnetic poles are not known to exist.
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If both assertion and reason are true and reason is the correct explanation of assertion.
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If both assertion and reason are true and reason is not the correct explanation of assertion.
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0%
If assertion is true but reason is false.
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If both assertion and reason are false.
Q.34.
Assertion : In water, value of magnetic field decreases.
Reason : Water is a diamagnetic substance.
Reason : Water is a diamagnetic substance.
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If both assertion and reason are true and reason is the correct explanation of assertion.
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If both assertion and reason are true and reason is not the correct explanation of assertion.
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If assertion is true but reason is false.
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If both assertion and reason are false.
Q.35.
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
Reason : The earth behaves as a magnet with the magnetic field pointing approximately from the geographic south to north
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If both assertion and reason are true and reason is the correct explanation of assertion.
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If both assertion and reason are true and reason is not the correct explanation of assertion.
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If assertion is true but reason is false.
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If both assertion and reason are false
Q.36.
If a magnetic material is having magnetic susceptibility $$(\chi)=-1$$, then the relative magnetic permeability $$(\mu_r)$$ and type of magnetic material is?
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$$0$$, diamagnetic
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$$2$$, ferromagnetic
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$$1$$, paramagnetic
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$$-1$$, diamagnetic
Q.37.
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.
Reason : Permanent magnet can be made by placing a ferromagnetic rod in a solenoid and passing current through it.
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If both assertion and reason are true and reason is the correct explanation of assertion.
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If both assertion and reason are true and reason is not the correct explanation of assertion.
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If assertion is true but reason is false.
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If both assertion and reason are false.
Q.38.
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.
Reason : Susceptibility is positive but very small for paramagnetic substance.
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If both assertion and reason are true and reason is the correct explanation of assertion.
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If both assertion and reason are true and reason is not the correct explanation of assertion.
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If assertion is true but reason is false.
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If both assertion and reason are false
Q.39.
Assertion : At high temperature, a ferromagnet becomes a paramagnet.
Reason : The ferromagnetic property depends on temperature.
Reason : The ferromagnetic property depends on temperature.
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If both assertion and reason are true and reason is the correct explanation of assertion.
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If both assertion and reason are true and reason is not the correct explanation of assertion.
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If assertion is true but reason is false.
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If both assertion and reason are false.
Q.40.
Which of the following is universal magnetic property?
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Ferromagnetism
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Diamagnetism
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Para magnetism
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Anti-ferromagnetism
Q.41.
A ball of superconducting material is dipped in liquid nitrogen and placed near a bar magnet. In which direction will it move?
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Away from bar magnet
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0%
Towards the bar magnet
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0%
Around the bar magnet
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Remain constant
Q.42.
Point out the correct set of diamagnetic substances.
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Aluminium, sodium calcium and oxygen
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Bismuth, copper, lead and silicon
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Cobalt, nickel, gadolinium and aluminium
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Silver, niobium, magnesium and calcium
Q.43.
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) $$\vec{E}$$ 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.
(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) $$\vec{E}$$ 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.
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Case (i) contradicts Gauss's law for electrostatic fields
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Case (ii) contradicts Gauss's law for magnetic fields
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Case (i) agree with $$\oint \vec{E}\cdot \vec{dl}=0$$
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Case (ii) contradicts $$\oint \vec{H}\cdot \vec{dl}=I_{en}$$
Q.44.
Some equipotential surfaces of the magnetic scalar potential are shown in figure. Magnetic field at a point in the region is:
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$$10^{-4}$$T
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0%
$$0.5\times 10^{-4}$$T
-
0%
$$2\times 10^{-4}$$T
-
0%
None of these
Explanation
Q.45.
Core of electromagnets are made of ferromagnetic materials which have.
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Low permeability and low retentivity
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High permeability and high retentivity
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High permeability and low retentivity
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Low permeability and high retentivity
Q.46.
In a permanent magnet at room temperature.
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Magnetic moment of each molecule is zero
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The individual molecules have non-zero magnetic moment which are all perfectly aligned
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Domains are partially aligned
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Domains are all perfectly aligned
Q.47.
Permanent magnets are the substances having the property of.
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Ferromagnetism at room temperature for a long period of time
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Paramagnetism at room temperature for a long period of time
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Anti ferromagnetism at room temperature for a long period of time
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Diamagnetism at room temperature for a long period of time
Q.48.
Mark the correct set of ferromagnetic substances.
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Iron, cobalt and nickel
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0%
Iron, copper and lead
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0%
Silicon, bismuth and nickel
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0%
Aluminium, sodium and copper
Q.49.
Short Answer Type Question.
Which magnetic property is present in all substances?
Which magnetic property is present in all substances?
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Diamagnetism
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0%
massless
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0%
frictionless
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0%
no common property
Q.50.
In the region closer to the oscillating charges, the phase difference between $$\overrightarrow { E } $$ and $$\overrightarrow { B } $$ fields is _____ and their magnitude quickly decreases as _____ with distance $$r$$ from the source.
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$$0,{ r }^{ -1 }$$
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$$\cfrac { \pi }{ 2 } ,{ r }^{ -1 }$$
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$$\cfrac { \pi }{ 2 } ,{ r }^{ -3 }$$
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$$0,{ r }^{ -3 }$$