JEE Questions for Physics Magnetism And Matter Quiz 13 - MCQExams.com

Assertion When radius of circular loop carrying current is doubled, its magnetic moment becomes four times.
Reason Magnetic moment depends on area of the loop.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion If a compass needle be kept at magnetic north pole of the earth, the compass needle may stay in any direction.
Reason Dip needle will stay vertical at the north pole of earth.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true
Assertion A compass needle when placed on the magnetic north pole of the earth rotates in vertical direction.
Reason The earth has only horizontal component of its magnetic field at the north poles.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Two short magnets are placed on a cork which floats on water. The magnets are placed such that the axis of one produced bisects the axis of other at right angles. Then the cork has neither translational nor rotational motion.
Reason Net force on the cork is zero.
Physics-Magnetism and Matter-78320.png
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The ferromagnetic substances do not obey Curie\'s law.
Reason At Curie point a ferromagnetic substance start behaving as a paramagnetic substance.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The properties of paramagnetic and ferromagnetic substances are not affected by heating.
Reason As temperature rises, the alignment of molecular magnets gradually decreases.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Soft iron is used as transformer core.
Reason Soft iron has narrow hysteresis loop.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Magnetism is relativistic.
Reason When we move along with the charge so that there is no motion relative to us, we find no magnetic field associated with the charge.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The earth\'s magnetic field does not affect the working of a moving coil galvanometer.
Reason Earth\'s magnetic field is very weak.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Diamagnetic materials can exhibit magnetism.
Reason Diamagnetic materials have permanent magnetic dipole moment.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion For making permanent magnets, steel is preferred over soft iron.
Reason As retentivity of stell is smaller.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Gauss\'s theorem is not applicable in magnetism.
Reason Mono magnetic pole does not exist
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion When a magnet is brought near iron nails, only translatory force acts on it.
Reason The field due to a magnet is generally uniform.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion When a magnetic dipole is placed in a non uniform magnetic field, only a torque acts on the dipole.
Reason Force would also act on dipole if magnetic field were uniform.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion Reduction factor (K) of a tangent galvanometer helps in reducing deflection due to current.
Reason Reduction factor increases with increase of current.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The susceptibility of diamagnetic materials does not depend upon temperature.
Reason Every atom of a diamagnetic material is not a complete magnet in itself.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion The permeability of a ferromagnetic material is independent of the magnetic field.
Reason Permeability of a material is a constant quantity.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion For a perfectly diamagnetic substance permeability is always one.
Reason The ability of a material of permit the passage of magnetic lines of force through it is called magnetic permeability.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
Assertion A paramagnetic sample displays greater magnetization (for the same magnetizing field) when cooled.
Reason The magnetization does not depend on temperature.
  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
  • If both Assertion and Reason are true but Reason is not the correct explanation of the Assertion.
  • If Assertion is true but Reason is false.
  • If the Assertion and Reason both are false.
  • If Assertion is false but Reason is true.
A compass needle whose magnetic moment is 60 amp × m2 pointing geographical north at a certain place, where the horizontal component of earth\'s magnetic field is 40 µ Wb/m2, experiences a torque 1.2 × 10–4 N × m. What is the declination at this place?
  • 30°
  • 45°
  • 60°
  • 25°
The distance between the poles of a horse shoe magnet is 0.1 m and its pole strength is 0.01 amp–m. The induction of magnetic field at a point midway between the poles will be
Physics-Magnetism and Matter-78326.png
  • 2 × 10–5 T
  • 4 × 10–6 T
  • 8 × 10–7 T
  • Zero
Due to a small magnet, intensity at a distance x in the end on position is 9 gauss. What will be the intensity at a distance x/2 on broad side on position?
  • 4 gauss
  • 36 gauss
  • 9 gauss
  • 4.5 gauss
The length of a magnet is large compared to it\'s width and breadth. The time period of its oscillation in a vibration magnetometer is T. The magnet is cut along it\'s length into six parts and these parts are then placed together as shown in the figure. The time period of this combination will be
Physics-Magnetism and Matter-78329.png

  • Physics-Magnetism and Matter-78330.png
  • 2)
    Physics-Magnetism and Matter-78331.png

  • Physics-Magnetism and Matter-78332.png
  • Zero
The needle of a deflection galvanometer shows a deflection of 60° due to a short bar magnet at a certain distance in tan A position. If the distance is doubled, the deflection is

  • Physics-Magnetism and Matter-78334.png
  • 2)
    Physics-Magnetism and Matter-78335.png

  • Physics-Magnetism and Matter-78336.png

  • Physics-Magnetism and Matter-78337.png
The area of hysteresis loop of a material is equivalent to 250 joule. When 10 kg material is magnetized by an alternating field of 50 Hz then energy lost in one hour will be (density of material is 7.5 gm/cm3)
  • 6 × 104 J
  • 6 × 104 erg
  • 3 × 102 J
  • 3 × 102 erg
A magnetized wire of moment M is bent into an arc of a circle subtending an angle of 60° at the centre; then the new magnetic moment is
Physics-Magnetism and Matter-78340.png
  • (2M / π)
  • (M / π)

  • Physics-Magnetism and Matter-78341.png
  • (3M / π)
A tangent galvanometer shows a deflection 45° when 10 mA current passes through it. If the horizontal component of the earth\'s field is 3.6 × 10–5 T and radius of the coil is 10 cm. The number of turns in the coil is
  • 5700 turns
  • 57 turns
  • 570 turns
  • 5.7 turns
A magnet is parallel to a uniform magnetic field. If it is rotated by 60°, the work done is 0.8 J. How much work is done in moving it 30° further
  • 0.8 × 107 erg
  • 0.4 J
  • 8 J
  • 0.8 erg
Susceptibility of Mg at 300 K is 1.2 × 10–5. The temperature at which susceptibility will be 1.8 × 10–5 is
  • 450 K
  • 200 K
  • 375 K
  • None of these
Three identical bar magnets each of magnetic moment M are placed in the form of an equilateral triangle as shown. The net magnetic moment of the system is
Physics-Magnetism and Matter-78346.png
  • Zero
  • 2 M

  • Physics-Magnetism and Matter-78347.png

  • Physics-Magnetism and Matter-78348.png
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