The front compound wall of a house is decorated by wooden spheres of diameter 21 cm, placed on small supports as shown in Fig 13.32. Eight such spheres are used for this purpose, and are to be painted silver. Each support is a cylinder of radius

The front compound wall of a house is decorated by wooden spheres of diameter 21 cm, placed on small supports as shown in the given figure. Eight such spheres are used for this purpose, and are to be painted silver. Each support is a cylinder of radius 1.5 cm and height 7 cm and is to be painted black. Find the cost of paint required if silver paint costs 25 paise per cm^(2) and black paint costs 5 paise per cm^(2) .

A wooden article was made by scooping out a hemisphere from each end of a solid cylinder,as shown in Fig.13.11.If the height of the cylinder is 10 cm,and its base is of radius 3.5. find the total surface area of the article.

Two small charged metal sphere A and B are situated in a vaccum. The distance between the centres of the spheres is 12.0 cm, as shown in the fig. The charge on each sphere may be assumed to be a point charge at the centre of the sphere. Point P is a movable point that lies on the line joining the centres of the sphere and is distance x fromt he centre of sphere A. The variation with distance x fo the electric field strength E at point P as shown in the figure. Use fig to state and explain the distance x at which the rate of change of potential with distance is maximum and minimum.

A small conducting sphere of radius a mounted on an insulated handle and a positive charge q is inserted through a hole in the wall of a hollow conducting sphere of inner radius b and outer radius c. The hollow sphere is supported on an insulating stand and is initially uncharged. The small sphere is placed at the center of the hollow sphere. Neglect any effect of the hole. Which of the following statements will be true for this system?

A wooden toy rocket is in the shape of a cone mounted on a cylinder as shown in Fig. 16.36. The height of the entire rocket is 26 cm, while the height of the conical part is 6 cm. The base of the conical portion has a diameter of 5 cm, while the base diameter of the cylindrical portion is 3 cm. If the conical portion is to be painted orange and the cylindrical portion yellow, find the area of the rocket painted with each of these colours. (Take pi=3. 14 )