The figure of a plaster roll is given below. The radius of its base is `5 cm` and height is `8 cm`. We have to make a cylindrical tin case in which this plaster roll cain be inserted áccurately. How many such cylinders can be made from a rectangular tin sheet having a length of 1,6 metre and breadth `32 cm ?`
'(##VPU_HSS_MAT_IX_C11_E06_004_Q01##)'

A charged metallic sphere A is suspended by a nylon thread. Another charged metallic sphere B held by an insulating handle is brought close to 'A' such that the distance between their centres is 10cm as shown in the figure (a). The resulting repulsion of A is noted (for example, by shining a beam of light and measuring the deflection of its shadow on a screen). Spheres A and B are touched by uncharged spheres C and D respectively as shown in the fig (b). C and D are then removed and B is brought closer to A to a distance of 5.0cm between their centres as shoen in the fig(c). What is the expected repulsion of A on the basis of Coulomb's law? Spheres A and C and spheres B and D have identical sizes. Ignore the sizes of A and B in comparison to the separation between their centres. '(##VPU_HSS_PHY_XII_CO1_E01_005_Q01##)'