Dual Nature of Radiation and Matter — Physics STD 12 Science — Question

A thin straight infinitely long conducting wire having charge density λ is enclosed by a cylindrical surface of radius r and length l, its axis coinciding with the length of the wire. Find the expression for the electric flux through the surface of the cylinder.

Write the principle of capacitor.

A short bar magnet placed in a horizontal plane has its axis aligned along the magnetic north-sourth direction. Null points are found on the axis of the magnet at 14 cm from the centre of the magnet. The earth's magnetic field at the place is 0.36 G and the angle of dip is zero. What is the total magnetic field on the normal bisector of the magnet at the same distance as the null points (i.e. 14 cm) from the centre of the magnet? (at null points, field due to a magnet is equal and opposite to the horizontal component of earth's magnetic field).

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.

A uniformly charged conducting sphere of 2.4 m diameter has a surface charge density of 80.0 μC/m².

1. Find the charge on the sphere.
2. What is the total electric flux leaving the surface of the sphere?

Figure shows x-t graph of a particle. Find the time t such that the average velocity of the particle during the period 0 to t is zero.

Two electric bulbs P and Q have their resistances in the ratio of 1 : 2. They are connected in series across a battery. Find the ratio of the power dissipation of these bulbs.

A ray PQ incident normally on the refracting face BA is refracting in the prism BAC made of material of refractive index1.5. Complete the path of ray through the prism. From which face will the ray emerge? Justify your answer.