# A too simple question paper from Physics (Magnetic effects of current and magnetism) for class XII

If you find these question easy to answer, well and good. If you don’t, please revise these portions thoroughly. These are based on just the minimum level of learning expected from a Class XII student.

1. State Gauss theorem in magnetism.
2. Define the terms retentivity and coercivity.
3. Which direction will a magnetic compass show when it is kept horizontally at the magnetic north pole of earth?
4. Determine the magnitude and direction of magnetic field to be applied in a region with a vertical electric field 1000 V/m (downwards) where a proton has to move towards east with a speed of 100 m/s without any deflection. (Disregard the presence of earth’s magnetic field.)
5. Derive expression for the force on a current carrying conductor in a uniform magnetic field.
6. Using Ampere’s circuital law, derive an expression for the magnetic field at a point due to a straight conductor carrying current.
7. The radius of the first electron orbit of a hydrogen atom is 0.5 A. The electron moves in this orbit with a uniform speed of 2.2 x 106 m/s. What is the magnetic field produced at the centre of the nucleus due to the motion of this elecetron?
8. Derive the relation mr = 1+cm (relation between magnetic permeability and magnetic susceptibility)
9. Mention the magnetic elements of earth and define each.
10. Derive expression for the magnetic dipole moment of a revolving electron.
11. Describe the principle, construction and working of a cyclotron. Why electrons cannot be accelerated using a cyclotron?

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