A wire of length 2 metre carries a current 1 ampere, is bent to form a circle. The magnetic moment of the coil is :
  • 2π
  • π/2
  • π/4
  • 1/π
The magnetic field of a given length of a ware for single turn coil at its centre is B. Then.its value for two turns of coil will be :
  • B/4
  • B/2
  • 4B
  • 2B
When charged particle enters-a uniform magnetic field, its K.E.:
  • remains constant
  • increases
  • decreases
  • becomes zero
To convert galvanometer into voltmeter one should connect :
  • high resistance in series with galvanometer
  • low resistance in series with galvanometer
  • high resistance in parallel with galvanometer
  • low resistance in parallel with galvanometer
A charge q moves in a region, where electric field E and magnetic field B both exist, then force on it is :
  • \(\vec{F}\) = q(\(\vec{v}\)×\(\vec{B}\))
  • \(\vec{F}\) = q{\(\vec{E}\)×(\(\vec{v}\) × \(\vec{B}\))}
  • \(\vec{F}\) = q(\(\vec{E}\ )+ (\(\vec{B}\) × \(\vec{v}\))
  • \(\vec{F}\) = q(\(\vec{B}\) + (\(\vec{E}\) × \(\vec{v}\))
Isoclinic lines are the lines joining places with :
  • equal dip
  • equal declination
  • equal dip and declination
  • None of these
The most suitable metal for making permanent magnets is :
  • iron
  • steel
  • copper
  • aluminium
The SI unit of magnetic dipole moment is
  • Ampere
  • Ampere metre²
  • Tesla
  • None of these
Earth's magnetism was discovered by:
  • Gauss
  • Oersted
  • Ampere
  • Gilbert
According to Gauss's theorem in magnetism, surface integral of magnetic field intensity over a surface (closed or open) is always:
  • -1
  • 1
  • 0
  • infinity
Tesla is a unit of:
  • electric flux
  • magnetic flux
  • magnetic field
  • electric field
10 eV electron is circulating in a plane at right angle to a uniform field of magnetic induction 10-1 Wb/m² (1G). The orbital radius of electron is:
  • 12 cm
  • 16 cm
  • 11 cm
  • 18 cm
A cyclotron can be used to produce high energy:
  • neutrons
  • deutrons
  • β particles
  • α partifcles
The radius of the trajectory of a charged particle in a uniform magnetic field is proportional to the:
  • charge on the particle
  • energy of the particle
  • momentum of the particle
  • all the above
The force \(\vec{F}\) experienced by a particle of charge q moving with velocity \(\vec{v}\) in a magnetic field \(\vec{B\) is given by,
  • \(\vec{F}\) = q(\(\vec{F}\) × \(\vec{B}\))
  • \(\vec{F}\) = q(\(\vec{B}\) × (\(\vec{b}\))
  • \(\vec{F}\) = q(\(\vec{v}\) × (\(\vec{B}\))
  • \(\vec{F}\) = q(\(\vec{v}\) × \(\vec{B}\))
The torque acting on a magnetic dipole of moment [latex]\vec{p_m}[/latex] when placed in a magnetic field \(\vec{B}\) is:
  • pmB
  • \(\vec{p_m}\)× \(\vec{B}\)
  • \(\vec{p_m}\)\(\vec{B}\)
  • \(\frac{p_m}{B}\)
In thomson spectrograph \(\vec{E}\) ⊥ \(\vec{B}\), then velocity of electron beam will be:
  • |\(\vec{E}\)|/|\(\vec{B}\)|
  • \(\vec{E}\) × \(\vec{B}\)
  • |\(\vec{B}\)|/|\(\vec{E}\)|
  • E² / B²
0 h : 0 m : 1 s

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