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#### Electrostatics Three Marks Questions

12th Standard EM

Reg.No. :
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Physics

Time : 01:00:00 Hrs
Total Marks : 45
10 x 3 = 30
1. Calculate the electrostatic force and gravitational force between the proton and the electron in a hydrogen atom. They are separated by a distance of 5.3 × 10-11 m. The magnitude of charges on the electron and proton are 1.6 × 10-19 C. Mass of the electron is me = 9.1 × 10-31 kg and mass of proton is mp = 1.6 × 10-27 kg.

2. Consider four equal charges q1,q2, q3 and q4 = q = +1μC located at four different points on a circle of radius 1m, as shown in the figure. Calculate the total force acting on the charge q1 due to all the other charges.

3. Obtain the expression for capacitance for a parallel plate capacitor.

4. Obtain the expression for energy stored in the parallel plate capacitor.

5. Explain in detail the effect of a dielectric placed in a parallel plate capacitor.

6. Deduce an expression for the electric field due to the system of point charges.

7. Define potential difference and derive.

8. Derive the expressions for the potential energy of a system of point charges.

9. Deduce electric flus for closed surfaces.

10. Write the special features of Gauss law.