An early model of atom considered it to have a positively charged point nucleus of charge Ze, surrounded by a uniform density of negative charge up to a radius R. The atom as a whole is neutral. For this model, what is the electric field at a distance r from the nucleus? '(##VPU_HSS_PHY_XII_CO1_E01_013_Q01##)'

Consider the charges q,q, and -q placed at the vertices of an equilateral triangle as shown in the figure. What is the force on each charge? '(##VPU_HSS_PHY_XII_CO1_E01_007_Q01##)'

The figure shows tracks of three charged particles in a uniform electrostatic fiels. Give the signs of threes charges. Which particle has the highest charge to mass ratio? '(##VPU_HSS_PHY_XII_CO1_E02_014_Q01##)'

Two point charges q_(1) and q_(2) of magnitude +10^(-8)C and -10^(-8)C , respectively, are placed 0.1m apart. Calculate the electric field at points A, B, and C shown in figure. '(##VPU_HSS_PHY_XII_CO1_E01_009_Q01##)'

A point charge +10 muC is a distance 5cm directly above the centre of a square of side 10cm as shown in the figure. What is the magnitude of the electric flux through the square? [Hint: Think of the square as one face of cube with edge 10cm]. '(##VPU_HSS_PHY_XII_CO1_E02_018_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##)'