Electricity and Magnetism Quiz

In charging by induction,

• body to be charged must be an insulator

• body to be charged must be a semiconductor

• body to be charged must be a conductor

• any type of body can be charged by induction

Number of electrons present in a negative charge of 8 C is

• 5 × 10^19

• 2.5 × 10^19

• 12.8 × 10^19

• 1.6 × 10^19

SI unit of electrical permittivity is

• N-m2C–2

• Am–2

• NC–1

• CPN–1m–2

The intensity of electric field at the surface of conducting hollow sphere is 10 NC–1 and its radius is 10 cm. The value of electric field at the centre of sphere is

• zero

• 10 NC–1

• 1 NC–1

• 100 NC–1

Force between two charges varies with distance between them as

A charge q is placed at the centre of the line joining two equal charges Q and Q. The system of the three charges will be in equilibrium, if q is equal to

• – Q / 2

• – Q / 4

• + Q / 4

• + Q / 2

In the diagram shown below

• field strength at P is less than field strength at Q

• field strength at P and Q are equal

• field is more strong at P and less strong at Q

• cannot be tell from the figure

Two equal and opposite charges each of 2C are placed at a distance of 0.04 m. Dipole moment of the system will be

• 6 × 10–8 C-m

• 8 × 10–2 C-m

• 1.5 × 10–2 C-m

• 8 × 10–6 C-m

What is the angle between the electric dipole moment and the electric field strength due to it on the equatorial line?

• 0°

• 90°

• 180°

• None of these

In an electric field E, the torque acting on a dipole moment p is

• p . E

• p × E

• zero

• E × p