Home
Class 12
PHYSICS
The effective length of a magnet is 31.4...

The effective length of a magnet is 31.4 cm and its pole strength is 0.8 Am. The magnetic moment, if it is bent in the form of a semicircle is _____ `Am^(2)`.

A

1.6

B

0.16

C

1.2

D

0.12

Text Solution

Verified by Experts

The correct Answer is:
B
`31.4=pir`
`thereforer=(31.4)/pi=31.4/3.14=10cm`
`thereforer=0.1m`
`therefore2r=0.2m`
`thereforem=pxx2r`
= `0.8xx0.2=0.16Am^(2)`
Promotional Banner

Topper's Solved these Questions

  • MOVING CHARGES AND MAGNETISM

    KUMAR PRAKASHAN|Exercise SECTION D (MULTIPLE CHOICE QUESTIONS)|108 Videos

  • MAGNETISM AND MATTER

    KUMAR PRAKASHAN|Exercise SECTION D Multiple Choice Questions (MCQs) (MCQs asked in Competitive Exams) MCQs asked in Board Exam and GUJCET|7 Videos

  • RAY OPTICS AND OPTICAL INSTRUMENTS

    KUMAR PRAKASHAN|Exercise SECTION-D (MULTIPLE CHOICE QUESTIONS (MCQs))(MCQs ASKED IN COMPETITIVE EXAMS)|142 Videos

Similar Questions

Explore conceptually related problems

Pole strength of a magnet is 5 Am and the magnetic length of it is 10 cm. Calculate the magnetic dipole moment of it.

Show the magnetic dipole moment in terms of pole strength.

A magnetic wire of dipole moment 4pi Am^2 is bent in the form of semi-circle. The new magnetic moment is .......

A straight steel wire of length l has magnetic moment m. If the wire is bent in the form of a semicircle the new value of the magnetic dipole moment is ......... .

There are 50 turns per cm length in a very long solenoid. It carries a current of 2.5A. The magnetic field at its centre on the axis is ______ T.

Force acting on a magnetic pole of 7xx 10^(-2) Am is 31.5 N. Magnetic field at that point is …

A magnetic pole of bar magnet with pole strength of 100 Am is 20 cm away from the centre of a bar magnet. Bar magnet has pole-strength of 200 Am and has a length of 5 cm. If the magnetic pole is on the axis of the bar magnet, find the force on the magnetic pole.

What is the magnitude of the equatorial and axial fields due to a bar magnet of length 1.0 cm at a distance of 100 cm from its mid-point? The magnetic moment of the bar magnet is 0.314 Am^(2) ,

A magnetic needle is hung by an untwisted wire, so that it can rotate freely in the magnetic meridian. In order to keep it in the horizontal position, a weight of 0.1 g is kept or one end of the needle. If the magnetic pole strength of this needle is 10 Am, find the value of the vertical component of the earth's magnetic field. (g= 9.8 ms^(-2) )

KUMAR PRAKASHAN-MOVING CHARGES AND MAGNETISM-SECTION D (MCQs ASKED IN COMPETITIVE EXAMS)
  1. Consider a tightly wound 200 turn coil of radius 20 cm, carrying a cur...

    Text Solution

    |

  2. Ionized hydrogen atoms and alpha-particles with same momenta enters pe...

    Text Solution

    |

  3. The effective length of a magnet is 31.4 cm and its pole strength is 0...

    Text Solution

    |

  4. Equal currents are passing through two very long and straight parallel...

    Text Solution

    |

  5. A galvanometer of resistance 50Omega is connecter to a battery of 8 V ...

    Text Solution

    |

  6. Equal currents are passing through two very long and straight parallel...

    Text Solution

    |

  7. An alpha particle of mass m moves on a circular path of radius r in a ...

    Text Solution

    |

  8. A long straight wire in the horizontal plane carries a current of 50 A...

    Text Solution

    |

  9. A proton is moving perpendicular to a uniform magnetic field of 2.5 te...

    Text Solution

    |

  10. A particle of mass m and charge q is incident on xz plane with velocit...

    Text Solution

    |

  11. An electron having mass 9.1xx10^(-31)kg, charge 1.6xx10^(-19)C and mov...

    Text Solution

    |

  12. Two parallel very long straight wires carrying current of 5A each are ...

    Text Solution

    |

  13. A very long straight wire of radius r carries current I. Intensity of ...

    Text Solution

    |

  14. The dimensional formula of effective torsional constant of spring is ...

    Text Solution

    |

  15. There are 50 turns per cm length in a very long solenoid. It carries a...

    Text Solution

    |

  16. The gyromagnetic of an electron = specific charge of an electron.

    Text Solution

    |

  17. A straight wire of mass 200g and length 1.5m carries a current of 2A. ...

    Text Solution

    |

  18. Unit of Bohr magneton is …..

    Text Solution

    |

  19. Current sensivity of galvanometer in inversely proportional to……

    Text Solution

    |

  20. Frequency of cyclotron is independent of …….

    Text Solution

    |