According to Ampere's Circuital law
MCQ Questions for Class 12 Physics Chapter 4 Moving Charges and Magnetism with Answers
  • a
  • b
  • c
  • d
Two identical bar magnets each of dipole moment p and length I are perpendicular to each other as shown in Fig. The dipole moment of the combination is:
MCQ Questions for Class 12 Physics Chapter 4 Moving Charges and Magnetism with Answers
  • √2 p
  • \(\frac{p}{√2}\)
  • P
  • 2p
The current sensitibility of a moving coil galanometer increases with decrease in:
  • magnetic field
  • area of a coil
  • number of turns
  • None of these
A current carring coil is placed in a uniform magnetic field. If the coil turns through an angle θ, then the torque is directly proportional to:
  • sin θ
  • cos θ
  • cot θ
  • tan θ
The sensitivity of a tangent galvanometer can be increased by increasing:
  • the radius of the coil
  • the external magnetic field
  • the number of turns of the coil
  • all the above
The permeability of a paramagnetic substance is:
  • very large
  • small but more than unity
  • less than unity
  • negative
Which of the following shows that the earth behaves as a magnet?
  • Repulsion between like poles .
  • Attraction between unlike poles
  • Null points in the magnetic field of a bar magnet
  • No existence of isolated magnetic poles
What is the angle of dip at the magnetic poles?
  • 30°
  • 0°
  • 45°
  • None of these
A charged particle of mass m and charge q travels on a circular path of radius r i.e., perpendicular to the magnetic field B. The time taken by particle to complete on revolution is :
  • \(\frac{2πqB}{m}\)
  • \(\frac{2πm}{qB}\)
  • \(\frac{2πmq}{B}\)
  • \(\frac{2πq^2B}{m}\)
Circular loop of radius 0.0157 m carries a current 2 A. The magnetic field at the centre of the loop is :
  • 1.57 × 10-3Wb/m²
  • 8.0 × 10-5 Wb/m²
  • 2.0 × 10-3 Wb/m²
  • 3.l4 × 10-1 Wb/m²
What happens to the magnetic field at the centre of a circular current carrying coil if we double the radius of the coil keeping the current unchanged?
  • halved
  • doubled
  • quadrupled
  • remains unchanged
When we double the radius of a coil keeping the current through it unchanged, what happens to the magnetic field directed along its axis at far off points?
  • halved
  • doubled
  • quadrupled
  • remains unchanged
The strength of the magnetic field around an infinite current carrying conductor is :
  • same everywhere
  • inversely proportional to the distance
  • directly proportional to the distance
  • None of these
A current carrying power line carries current from west to east. Then the direction of the magnetic field 2 m above it is :
  • west to east
  • south to north
  • north to south
  • None of these
The force between two parallel current carrying conductors is F. If the current in each conductor is doubled, then the force between them becomes :
  • 4F
  • 2F
  • F
  • \(\frac{F}{4}\)
How much force will be experienced by a moving charge in a magnetic field? The symbols have their usual meanings.
  • \(\vec{F}\) = q(\(\vec{v}\).\(\vec{B}\))
  • \(\vec{F}\) = \(\frac{q}{(\vec{v}.\vec{B})}\)
  • \(\vec{F}\) = \(\frac{q}{2}\)\((\vec{v}×\vec{B}\))
  • \(\vec{F}\) = q(\(\vec{v}\)×\(\vec{B}\))
Which of the following is not a unit of magnetic induction?
  • gauss
  • tesla
  • oersted
  • weber/metre²
The magnetic field produced by an / meter long straight (x cry thin) current (I) carry ing conductor at any point on itself is :
  • zero
  • infinite
  • \(\frac{µ_0l}{4πl}\)
  • \(\frac{µ_0l}{2πl}\)
A charge + q is sent through a magnetic field. The force acting on it is maximum w hen the angle between the direction of motion of the charged particle and the magnetic field :
  • 0°
  • 45°
  • 90°
  • 180°
An electron having mass 'm' and Kinetic energy E enters in uniform magnetic field B perpendicular, then its frequency will be:
  • \(\frac{eE}{qmB}\)
  • \(\frac{2πm}{eB}\)
  • \(\frac{eB}{2πm}\)
  • \(\frac{2m}{eBE}\)
0 h : 0 m : 1 s

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