All types of questions in chapter – Electric charges and fields.
PART-A
Questions carrying ONE mark each.
1.What is the least possible value of charge?
2.Can a charge on a body be 1x 10″ C
3. What is quantization of a charge?
4. What is the basic unit of charge?
5. What happens to the mass of the body when it is charged negatively?
6. Write the SI unit of charge (Define SI unit of charge).
7. State Coulomb’s law
8.Write Coulomb’s law in vector form
9.How does the force between two point charges change, if the distance between them is doubled?
10.How does the force between two point charges change if the dielectric constant of the medium in which they are kept decreases?
11.Define relative permittivity of a medium in terms of force between electric charges.
12.What is an electric dipole?
13.Draw the electric field lines for a system of two positive point charges.
14.A cube encloses a charge of IC. What is the electric flux through the surface of the cube? 15. State Gauss’ law in electrostatics
PART-B
Questions carrying TWO marks each
- Write two fundamental properties of electric charge.
- Charge is quantized. Explain
- State and explain Coulomb’s law in electrostatics
- Write Coulomb’s law in vector form. Explain the terms.
- Define electric dipole moment. Write its S.I. unit
- Write two properties of electric field lines.
- Electric field lines never cross each other. Explain
- Draw pattern of electric field lines for
(i) a point charge
(ii) a system of two negative point charges of same magnitude (ii) in a uniform of electric field
9.Write the expression for electric intensity at a point due to point charge and explain the terms.
10.Define Linear charge density’ and surface charge density at a point.
11.Define volume charge density. Write its S.I unit.
12.An infinite line charge produces a field of 9 x 10′ N/C, at a distance of 2 cm. Calculate the linear charge density
PART-C
Questions carrying THREE marks each
1. Mention any three properties of an electric charge.
2.Using superposition principle, find the resultant force on a charge due to a multiple charges.
3.Derive an expression for torque acting on an electric dipole placed in a uniform electric field.
4.Write any three characteristics of electric field lines.
PART-D
Questions carrying FIVE marks each
1.Derive an expression for electric field due to an electric dipole at a point on the axial line.
2.Derive an expression for electric field at a point due to an electric dipole on the equatorial line.
3.State Gauss’ law in electrostatics. Using the law derive an expression for electric field due to a uniformly charged spherical shell at a point outside the shell.
4.Derive an expression for electric field at a point due to an infinitely long charged straight conductor
using Gauss’s law.
5.Using Gauss’s law derive an expression for the electric field at a point due to an uniform infinitely charged plane sheet.
PART-E (Numericals)
Questions carrying FIVE marks each
6.The electrostatic force on a metal sphere of charge 0.4 µC due to another identical metal sphere of charge -0.8 µC in air is 0.2 V. Find the distance between the two spheres and also the force between the same two spheres when they are brought into contact and the replaced in their initial position.
7.Two-point charges 1 x 10 C and 4 x 10 C are 0.06 m apart in air. Find the location of the point between then at which resultant electric field is zero.
8.Two point charges 4uC and 2uC are placed at vertices A and B of right angled triangle ABC respectively. B is the right angle AB=√3cm, AC = 2 cm and BC = 1 cm. Calculate the magnitude and direction of the resultant electric intensity at C.
9.Two charge +3 nC and -3 nC are placed 20 cm apart. Calculate the dipole moment and electric field due to the dipole at a point on the axis at a distance 0.04 m from the midpoint of the electric dipole.
10.A spherical conductor of radius 12 cm has a charge of 1.6 x 10°C distributed uniformly on its surface: What is the electric field (a) inside the sphere (b) just outside the sphere (e) at a point 18 cm from the centre of the sphere?
11.ABC is an equilateral triangle of side 0.1 m. Point charge of +9C and -9C are placed at corners A and B respectively. Calculate the resultant electric intensity at C.
12.Three charges each equal to +4 nC are placed at the three corners of a square of side 2 cm. Find the electric field at the fourth corner.
