Home
Class 12
PHYSICS
A magnetic needle has a frequency of 20 ...

A magnetic needle has a frequency of `20` oscillations per minute in the earth's horizontal field. When the field of a magnet supports the earths horizontal field, the frequency increases to `30` oscillations per minute. The ratio of the field of the magnet to that of the earth is

A

`4:7`

B

`7:4`

C

`5:4`

D

`4:5`

Text Solution

Verified by Experts

The correct Answer is:
C
`nalphasqrtBrArr20/30=sqrt((B_(H))/(B+B_(H)))rArrB=5/4B_(H)`
Promotional Banner

Topper's Solved these Questions

  • MAGNETISM AND MATTER

    NARAYNA|Exercise EXERCISE - 2 (H.W)|24 Videos

  • MAGNETISM AND MATTER

    NARAYNA|Exercise EXERCISE - 3|20 Videos

  • MAGNETISM AND MATTER

    NARAYNA|Exercise EXERCISE - 1 (H.W)|30 Videos

  • MAGNETISM

    NARAYNA|Exercise LEVEL-II (H.W)|24 Videos

  • MOVING CHARGES AND MAGNETISM

    NARAYNA|Exercise EXERCISE - 4|20 Videos

Similar Questions

Explore conceptually related problems

A magnetic needle has a frequency of 20 oscillations per minute in the earth's horizontal field. When the field of a manget supports the earths horizontal field, the frequency increases to 30 oscillations per minute. The ration of the field of the magnet to that of the earth is

Lines of force due to earth's horizontal magnetic field are

A small magnetic needle performs 10 oscillations/minute in the earth's horizontal magnetic field . When a bar magnet is placed near the small magnet in same position , frequency of oscillations becomes 10sqrt2 oscillations/minute . If the bar magnet be turned around end to end , the rate of oscillation of small magnet will become

A compose needle makes 10 oscillations per minute in the earths horizontal field. A bar magnet deflects the needle by 60^(@) from the magnetic meridian. The frequency of oscillaiton in the deflected position in oscillations per minute is (field due to magnet is perpendicular to B_(H) )

The magnetic needle of an oscillation magnetometer makes 10 oscillations per minut under the action of earth's magnetic field along. When a bar magnet is placed at some distance along the axis of the needle it makes 14 oscillations per minute. If the bar magnet is turned so that its poles interchange their position, then the new frequency of oscillation of the needle is:

The magnetic needle of a vibration magnetometer makes 12 oscillations per minute in the horizontal component of earth's magnetic field. When an external short bar magnet is placed at some distance along the axis of the needle in the same line it makes 15 oscillations per minute. If the poles of the bar magnet are inter changed, the number of oscillations it takes per minute is

The time period of a bar magnet suspended horizontally in the earth's magnetic field and allowed to oscillate

If the period of oscillaion of freely suspended bar magnet in earth's horizontal field H is 4 sec. When another magnet is brought near it, the period of oscillation is reduced to 2s. The magnetic field of second bar magnet is

A magnet of magnetic moment M oscillating freely in earth's horizontal magnetic field makes n oscillations per minute. If the magnetic moment is quadrupled and the earth's field is doubled, the number of oscillations mode per minute would be

NARAYNA-MAGNETISM AND MATTER-EXERCISE - 2 (C.W)
  1. A bar magnet is placed with its North pole pointing North. Neutral poi...

    Text Solution

    |

  2. The period of a thin magnet in a magnetic field is 2s. It is cut into ...

    Text Solution

    |

  3. A bar magnet suspended in magnetic meridian executes oscillations with...

    Text Solution

    |

  4. Two bar magnets are bound together side by side and suspended. They sw...

    Text Solution

    |

  5. A short bar magnet is oscillating in a magnetic field and its time per...

    Text Solution

    |

  6. When two identical bar magnets placed one above the other, such that t...

    Text Solution

    |

  7. A bar magnet suspended freely in uniform magnetic field is vibrating w...

    Text Solution

    |

  8. A short bar magnet of magnetic moment 2Am^(2) and moment of inertia 6x...

    Text Solution

    |

  9. The period of oscillation of a magnet at a place is 4seconds. When it ...

    Text Solution

    |

  10. The magnetic needle of a vibration magnetometer makes 12 oscillations ...

    Text Solution

    |

  11. The magnetic needle of a V.M.M completes 10 oscillations in 92seconds....

    Text Solution

    |

  12. A magnetic needle has a frequency of 20 oscillations per minute in the...

    Text Solution

    |

  13. A thin iron rod is cut into 10 equal parts parallel to its length. The...

    Text Solution

    |

  14. The dipole moment of each molecule of a paramagnetic gas is 1.5xx10^(-...

    Text Solution

    |

  15. A paramagnetic sample shows a net magnetisation of 8Am^-1 when placed ...

    Text Solution

    |

  16. The angle of dip at a place is 40.6^(@) and the intensity of the verti...

    Text Solution

    |

  17. The correct value of dip angle at a place is 45^(@). If the dip circle...

    Text Solution

    |

  18. A compass needle oscillates 20 times per minute at a place where the d...

    Text Solution

    |

  19. The real angle of dip, if a magnet is suspended at an angle of 30^(@) ...

    Text Solution

    |

  20. At a place the value of B(H) and B(V) are 0.4xx10^(-4)T and 0.3xx10^(-...

    Text Solution

    |