With the help of ray diagram explain what do marginal and paraxial rays mean.

With the help of a labelled diagram, explain the principle and working of a moving coil galvanometer.

With the help of a circuit diagram explain the function of a shunt used in a galvanometer.

Show with the help of a ray diagram how the image is formed in an astronomical telescope .

With the help of an example explain how do tranquilizers control the feeling of depression?

Show that for refraction of light through a parallel glass slab, the incident ray and the emergent ray are parallel to each other. Or, With the help of a diagram show how in case of a rectangular glass slab, when light is refracted by the two parallel faces of the slab, deviation between angle of incidence and angle of refractive is zero.

What is the charge of X-rays?

An object is placed in front of a convex mirror on the principal axis. With the help of a ray diagram show the position of the image.

What are radioactive rays ?

What do you mean by hard and soft X-ray ?