Electrostatics Test-1

Electrostatics means?

• Study of Electric current

• Study of charges in motion

• Study of charges at rest

• All the above

Name the physical quantities whose unit is J/C

• electric field

• electric potential

• dipole moment

• none of the above

Force between two point charges kept at a distance ‘r’ is F. What is the distance between them, if the force between them reduces to F/3

• ³√r

• 3r

• ²√r

• none of these

An electric field required to keep a water drop of mass m just to remain suspended, when charged with one electron is:

• e m / g

• m g / e

• e m g

• m g

An electric dipole is placed inside a hollow sphere at its center. Then,

• the electric flux through the sphere is zero.

• the electric field is zero at every point on the surface of the sphere.

• the electric field is non-zero at every point on the surface of sphere.

• none of these.

If the amounts of electric flux entering and leaving an enclosed surface respectively are ф₁ and ф₂, the electric charge inside the surface will be:

• (ф₂ – ф₁). ℇ_o

• (ф_{2 +} ф₁). ℇ_o

• (ф₂ – ф₁)/ ℇ_o

• (ф₂ + ф₁)/ ℇ_o

An electric charge q is placed at one of the corner of a cube of side a. the electric flux on one of its faces will be:

• q / 6 ℇ₀

• q / 6² ℇ₀

• q / 4 π 6² ℇ₀

• q / 24 ℇ₀

What is not true for equipotential surface for a uniform electric field?

• equipotential surface is flat

• equipotential surface if spherical

• work done is zero

• electrical lines of force are perpendicular to the surface

If there are n capacitors in parallel connected to V volt source, then the energy stored is equal to:

• C V

• n C V²/2

• C V²

• C V²/ 2n

A capacitor is charged by connecting a battery across its plates. It stores energy U. Now the battery is disconnected and another identical capacitor is connected across it. Then, the energy stored by both the capacitors of the system will be:

• U

• U/2

• 3U/2

• U/4