Home
Class 12
PHYSICS
A flat dielectric disc of radius R carri...

A flat dielectric disc of radius `R` carries an excess charge on its surface. The surface charge density `sigma`. The disc rotastes about an axis perpendicular to its lane passing thrugh the centre with angulasr velocity `omega`. Find the toruque on the disc if it is placed in a uniform magnetic field `B` directed perpendicular to the rotation axis.

Text Solution

Verified by Experts

`pi sigma omega r^3 Bdr and tau = pi sigmaomegaB int_(0)^(a)r^3 dr = (pi sigmaomegaBa^4)/(4)`
Promotional Banner

Topper's Solved these Questions

  • ELECTROMAGNETICS

    AAKASH SERIES|Exercise ADDITIONAL EXERCISE|13 Videos

  • ELECTROMAGNETICS

    AAKASH SERIES|Exercise PROBLEMS (LEVEL -I)|40 Videos

  • ELECTROMAGNETIC WAVES

    AAKASH SERIES|Exercise EXERCISE -II|22 Videos

  • ELECTROSTATICS

    AAKASH SERIES|Exercise ADDITIONAL PRACTICE EXERCISE (PRACTICE SHEET (ADVANCED) INTEGER TYPE QUESTIONS)|5 Videos

Similar Questions

Explore conceptually related problems

A flat insulating disc of radius 'a' carries an excess charge on its surface is of surface charge density sigma C//m^(2) . Consider disc to rotate around the axis passing through its centre and perpendicular to its plane with angular speed omega rad/s. If magnetic field vecB is directed perpendicular to the rotation axis, then find the torque acting on the disc.

A disc of mass m has a charge Q distributed on its surface. It is rotating about an XX' with a angular velocity omega . The force acting on the disc is

A sphere of radius R, uniformly charged with the surface charge density sigma rotates around the axis passing through its centre at an angular velocity. (a) Find the magnetic induction at the centre of the rotating sphere. (b) Also, find its magnetic moment.

One quarter sector is cut from a uniform circular disc of radius R. The sector has mass M. IT is made to rotate about a line perpendicular to its plane and passing through the centre of the original disc. Its moment of inertia about the axis of rotation is

A charge Q is uniformly distributed over the surface of non - conducting disc of radius R . The disc rotates about an axis perpendicular to its plane and passing through its centre with an angular to its plane and passing through its centre of the disc. If we keep both the amount of charge placed on the disc and its angular velocity to be constant and vary the radius of the disc then the variation of the magnetic induction at the centre of the disc will br represented by the figure:

A nonconducing disc of radius R is rotaing about axis passing through its cente and perpendicual its plance with an agular velocity omega . The magnt moment of this disc is .

Circular disc of mass 2 kg and radius 1 m is rotating about an axis perpendicular to its plane and passing through its centre of mass with a rotational kinetic energy of 8 J. The angular momentum is (Js) is

A metal disc of radius R rotates with an angular velcoity omega about an axis perpendiclar to its plane passing through its centre in a magnetic field B acting perpendicular to the plane of the disc. Calculate the induced emf between the rim and the axis of the disc.

The moment of inertia of a copper disc, rotating about an axis passing through its centre and perpendicular to its plane

A disc of radius R is pivoted at its rim. The period for small oscillations about an axis perpendicular to the plane of disc is

AAKASH SERIES-ELECTROMAGNETICS-PROBLEMS (LEVEL -II)
  1. A rectangular loop of wire is oriented with the left corner at the ori...

    Text Solution

    |

  2. Two coils each of 100 turns are held at right angles such that one lie...

    Text Solution

    |

  3. Magnetic field at a distance a from long current carrying wire is prop...

    Text Solution

    |

  4. A system of long four parallel conductors whose sections with the plan...

    Text Solution

    |

  5. A cylindrical conductor of radius R carries a current along its length...

    Text Solution

    |

  6. A square current carrying loop made of thin wire and having a mass m=1...

    Text Solution

    |

  7. A current I flows through an infinitly long wire having infinite brand...

    Text Solution

    |

  8. Figure here shows three cases, in all cases the circular path has radi...

    Text Solution

    |

  9. Find magnetic field at O due to the current carrying conductor as show...

    Text Solution

    |

  10. Two identical particles having the same mass m and charges +q and - q ...

    Text Solution

    |

  11. In the figure shown, a semi-circular wire loop of radius R is placed i...

    Text Solution

    |

  12. A flat dielectric disc of radius R carries an excess charge on its sur...

    Text Solution

    |

  13. Consider a solid sphere of radius r and mass m which has charge q dist...

    Text Solution

    |

  14. A thin uniform ring of radius R carrying charge q and mass m rotates a...

    Text Solution

    |

  15. A wire carrying current i has the configuration as shown in figure. Tw...

    Text Solution

    |

  16. A uniform constant magnetic field B is directed at an angle of 45^(@) ...

    Text Solution

    |

  17. A sphere of radius R, uniformly charged with the surface charge densit...

    Text Solution

    |

  18. A ring of radius R having uniformly distributed charge Q. is mounted o...

    Text Solution

    |

  19. Given figure shows a coil bent with all edges of length 1 m and carryi...

    Text Solution

    |

  20. A long, straight wire carries a current i. A particle having a positiv...

    Text Solution

    |