Science (English Medium) इयत्ता १२ - CBSE Question Bank Solutions

A short bar magnet has a magnetic moment of 0.48 J T⁻¹. Give the direction and magnitude of the magnetic field produced by the magnet at a distance of 10 cm from the centre of the magnet on

1. the axis,
2. the equatorial lines (normal bisector) of the magnet.

A uniform magnetic field of 3000 G is established along the positive z-direction. A rectangular loop of sides 10 cm and 5 cm carries a current of 12 A. What is the torque on the loop in the different cases shown in fig.? What is the force on each case? Which case corresponds to stable equilibrium?

Why does a paramagnetic sample display greater magnetisation (for the same magnetising field) when cooled?

Why is diamagnetism, in contrast, almost independent of temperature?

If a toroid uses bismuth for its core, will the field in the core be (slightly) greater or (slightly) less than when the core is empty?

Is the permeability of a ferromagnetic material independent of the magnetic field? If not, is it more for lower or higher fields?

Magnetic field lines are always nearly normal to the surface of a ferromagnet at every point. (This fact is analogous to the static electric field lines being normal to the surface of a conductor at every point.) Why?

Would the maximum possible magnetisation of a paramagnetic sample be of the same order of magnitude as the magnetisation of a ferromagnet?

Explain qualitatively on the basis of domain picture the irreversibility in the magnetisation curve of a ferromagnet.

What kind of ferromagnetic material is used for coating magnetic tapes in a cassette player, or for building ‘memory stores’ in a modern computer?

A certain region of space is to be shielded from magnetic fields. Suggest a method.

A Rowland ring of mean radius 15 cm has 3500 turns of wire wound on a ferromagnetic core of relative permeability 800. What is the magnetic field B in the core for a magnetising current of 1.2 A?

A power transmission line feeds input power at 2300 V to a stepdown transformer with its primary windings having 4000 turns. What should be the number of turns in the secondary in order to get output power at 230 V?

Consider the motion of a charged particle in a uniform magnetic field directed into the paper. If velocity v of the particle is in the plane of the paper the charged particle will ______.

Nickel shows ferromagnetic property at room temperature. If the temperature is increased beyond curie temperature, then it will show ______.

The frequency of γ-rays, X-rays and ultraviolet rays are a, b and c respectively. Then, ______.

In interaction of radiation with matter, radiation behaves as if it is made up of particles called ______.

In a region, the potential is represented by V(x, y, z) = 6x – 8xy – 8y + 6yz, where V is in volts and x, y, z are in metres. The electric force experienced by a charge of 2 coulomb situated at point (1, 1, 1) is ______.

The given figure represents a material which is ______.