Magnetism and Matter — Physics STD 12 Science — Question

A force F facts on a point charge placed on the axis of an electric dipole. If the distance of a point charge from the dipole is doubled, what will be the force on it? Explain the reason also.

Explain about super conductor materials with respect to their magnetic properties.

Explain, with the help of a circuit diagram, the working of a p-n junction diode as a half-wave rectifier.

Can the potential difference across a battery be greater than its emf?

Write the equation of P.E. of electric dipole in external electric field and discuss its special cases.

Give a physical explanation of the fact that the potential energy of a positive charge coupled is positive.

A point source is placed at a depth h below the surface of water (refractive index = μ).

1. Show that light escapes through a circular area on the water surface with its centre directly above the point source.
2. Find the angle subtended by a radius of the area on the source.

In a double-slit experiment the angular width of a fringe is found to be 0.2° on a screen placed 1 m away. The wavelength of light used is 600 nm. What will be the angular width of the fringe if the entire experimental apparatus is immersed in water? Take refractive index of water to be 4/3.

A pivoted aluminium bar falls much more slowly through a small region containing a magnetic field than a similar bar of an insulating material. Explain.