Explain the process of secondary treatment given to the primary effluent upto the point it shows significant change in level of its BOD.

Explain the process of secondary growth in the stems of woody angiosperms with the help of schematic diagrams. What is its significance?

Draw a simple circuit of a CE transistor amplifier. Explain its working. Show that the voltage gain, A_V of the amplifier is given by A_v = - ( beta_(ac) R_L )/(r_i) where beta_(Ac) is the current gain, R_L is the load resistance and r_1 is the input resistance of the transistor. What is the significance of the negative sign in the expression for the voltage gain?

Show diagramatically two different arrangements used for winding the primary and secondary coils in a transformer. Assuming the transformer to be an ideal one write expressions fo rthe ratio of its output current to input current in terms of the number of turns in the primary and secondary coils. Mention two reasons for energy losses in an actual transformer.

A small sphere rolls down without slipping from the top of a track in a vertical plane. The track has an elevated section and a horizontal part is 1.0 m above the ground level and the top of the track is 2.4 m above the ground. Find the distance on the ground with respect to the point B (which is vertically ) below the end of the track as shown in figure. Where the sphere lands. During its flight as a projectile does the sphere continue to rotate about its centre of mass? Explain.

For a circular coil of radius R and N turns carrying current I, the magnitude of the magnetic field at a point on its axis at a distance x from its centre is given by, B= (mu_0IR^2N)/(2(x^2+R^2)^(3/2)) . Consider two parallel co-axial circular coils of equal radius R, and number of turns N, carrying equal currents in the same direction, and separated by a distance R. Show that the field on the axis around the mid-point between the coils is uniform over a distance that is small as compared to R, and is given by, B=0.72 (mu_0NI)/R approximately.

For a circular coil of radius R and N turns carrying current I, the magnitude of the magnetic field at a point on its axis at a distance x from its centre is given by, B= (mu_0IR^2N)/(2(x^2+R^2)^(3/2)) . Show that this reduces to the familiar result for field at the centre of the coil.