A magnetic bar of M magnetic moment is placed m the field of magnetic strength B, the torque acting on it is :
  • \(\vec{M}\).\(]\vec{B}\)
  • -\(\vec{M}\).\(\vec{B}\)
  • \(\vec{M}\) × \(\vec{B}\).
  • \(\vec{B}\) × \(\vec{M}\)
The magnetic lines of force inside a bar magnet:
  • do not exist
  • depends on area of cross-section of bar magnet
  • are from N-pole to S-pole of the magnet
  • are from S-pole to N-pole of the magnet.
A magnetic dipole moment is a vector quantity directed from:
  • S to N
  • N to S
  • E to W
  • W to E
S.I. unit of flux is :
  • Ohm
  • Weber
  • Tesla
  • None
What is the angle of dip at a place where the horizontal component of earth's magnetic field is equal to the vertical component?
  • 0°
  • 30°
  • 45°
  • 90°
Which of the following has a low value in ferrites?
  • Conductivity
  • Permeability
  • Magnetic susceptibility
  • All the above
The dimensional representation of magnetic flux density is :
  • [MLT-2]
  • [MLT-2A-1]
  • [MLT-2A-2]
  • [MT-2A-1]
Tangent law is applicable only when:
  • two uniform and mutually perpendicular magnetic fields exist
  • two magnetic fields exist
  • horizontal component of earth's magnetic field is present
  • uniform magnetic field are used
Ferrites may be:
  • ant. ferromagnetic
  • ferromagnetic
  • ferrimagnetic
  • None of the above
What is the magnetic field in the empty space enclosed by the toroidal solenoid of radius ‘R’? ,
  • Infinity
  • \(\frac{µ_0}{4π}\).\(\frac{2πl}{R}\)
  • \(\frac{µ_0}{4π}\).(\(\frac{πl}{R}\))
  • zero
A current carrying power line carries current from west to east. What will be direction of magnetic field 1 meter above it?
  • N to S
  • S to N
  • E to W
  • W to E
The dimensional representation of \(\sqrt{l/MB}\) is similar to that of:
  • frequency
  • time
  • distance
  • speed
On quadrupling the moment of inertia of a magnet, its frequency of oscillation will become:
  • half
  • double
  • four times
  • one-fourth
The magnetic field strength due to a short bar magnet directed along its axial line at a distance r is B. What is its value at the same distance along the equatorial line?
  • B
  • 2B
  • \(\frac{B}{2}\)
  • \(\frac{B}{4}\)
The neutral point in the magnetic field of a horizontally placed bar magnet is a point where the magnetic field due to that bar magnet is:
  • zero
  • more than that of earth
  • less than that of earth
  • equal to that of earth
In a moving coil galvanometer, we use a radial magnetic field so that the galvanometer scale is :
  • exponential
  • linear
  • algebraic
  • logarithmic
The force between two parallel wire 2 × 10-7 Nm-1, placed 1 m apart to each other in vacuum. The electric current flowing through the wires is:
  • 1 A
  • zero
  • 5 × 106 A
  • 2 × 10-7 A
The force acting per unit length of a semi circular wire of radius R carrying a current I is:
  • \(\frac{µ_0l^2}{4R}\)
  • \(\frac{µ_0l^2}{2R}\)
  • \(\frac{µ_0l^2}{R}\)
  • \(\frac{2µ_0l^2}{R}\)
Which of the following has higher magnetic susceptibility?
  • diamagnetic
  • paramagnetic
  • ferromagnetic
  • None of these
The magnetic field of earth is due to:
  • induction effect of the sun
  • the presence of a large magnet at the centre of the earth
  • interaction of cosmic rays with the current of earth
  • motion and distribution of some material in an outside the earth
0 h : 0 m : 1 s

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