Electric potential and capacitance (Class 12)

What is the relationship between electric field (E) and electric potential (V) at a point?

• E= dV⁄dr

• E= -dV/dr

• V= dE/dr

• V= -dE/dr

The physical quantity whose S.I. unit is coulomb/volt is

• Electric field intensity

• Electric potential

• Capacitance

• Dipole moment

Two protons A and B are placed between two parallel plates having a potential difference V as shown in the figure. The force experienced by ___

• A and B are equal

• A is greater than B

• B is greater than A

• A and B cannot be calculated

A dipole placed in an uniform electric field, the angle θ between dipole moment and elelctric field is zero then,

• U= -pE, torque= 0

• U= -pE, torque= pE

• U= 0, torque= -pE

• U= pE, torque= -pE

A hollow metal sphere of radius 5 cm is charged such that the potential on its surface is 10V. The potential at the centre of the sphere is

• 10 V

• 0 V

• Same as at a point 5 cm away from the surface

• Same as at a point 25 cm away from the surface

Charge on a capacitor varies with voltage V as shown. The area of the triangle OAB represents

• Capacitance

• Capacitive reactance

• Magnetic field between the plates

• Energy stored in the capacitor

When a dielectric of dielectric constant K is introduced between the plates of a parallel plate capacitor, the field at a point between the plates:

• increases

• remains the same

• becomes K times E

• becomes E/K

Identify the incorrect statement.

• An equipotential surface has constant value of potential at all points on the surface.

• Equipotential surface of a single point charge are concentric spherical surfaces centred at the charge.

• The electric field at every point is parallel to the equipotential surfaces passing through that point.

• The work done in moving a unit test charge between two points in an equipotential surface is zero.

Identify the correct statement.

• There is a non zero electric field inside a conductor.

• The electrostatic field at the surface of a charged conductor must be normal to the surface at every point.

• The interior of a conductor can have exess charge in the static situation.

• Electrostatic potential is not constant throughout the volume of the conductor, it has different values on its surface and inside.

Which of the following is a polar molecule?

• H₂

• Cl₂

• O₂

• HCl