Classes
Class 9Class 10First YearSecond Year  $12.11 In Bohrs atomic model of hydrogen atom the electron is in an orbit around the nuclear proton at a distance of 5.29 \times 10^{-11} " \mathrm{m} with a speed of 2.18 \times 10^{6} \mathrm{~ms}^{-1} . \left(e=1.60 \times 10^{-10} \mathrm{C}\right. mass of electron \left.=9.10 \times 10^{-31} \mathrm{~kg}\right) . Find(c) The ionization energy for the atom in eV$  $Three capacitors of capacitance 2 \mu \mathrm{F} each are connected in parallel. Their equivalent capacitance will be:A) 0.66 \mu \mathrm{F} B) 4 \mu \mathrm{F} C) 6 \mu \mathrm{F} D) 1.5 \mu \mathrm{F}$  $13.6. A point charge of +2 \mathrm{C} is transferred from a point at potential 100 \mathrm{~V} to a point at potential 50 \mathrm{~V} . What would be the energy supplied by the charge?Ans. (100J)$  $13.19. What are hazards of staticelectricity?$  $13.3. The force of repulsion between two identical positive charges is 0.8 \mathrm{~N} when the charges are 0.1 \mathrm{~m} apart. Find the value of each charge.Ans. \left(9.4 \times 10^{-7} \mathrm{C}\right)$  $13.16. What is difference between variable and fixed type capacitor?$  