Electrostatics 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

When an electric dipole p is placed in a uniform electric field E, then at what angle between p and E the value of torque will be maximum?

• 90°

• 0°

• 180°

• 45°

In a system, n' electric dipole are placed in a closed surface. The value of emergent electric flux from enclosed surface is

• qε0

• 2qε0

• 2qε0

• zero

Gauss' law is true only if force due to charges varies as

• r–1

• r–2

• r–3

• r–4

For a given surface, the ∮E.dS=0. From this, we can conclude that

• E is necessarily zero on the surface

• E is perpendicular to the surface at every point

• the total flux through the surface is zero

• the flux is only going out of the surface

Which of the following is not a unit of electrostatic potential?

• Volt

• Joule/coulomb

• Newton/Coulomb

• Newton-metre/Coulomb

If electrostatic potential at the surface of a Hollow conducting sphere of 5 cm radius is 50 V, then the potential at the centre of sphere will be

• 10 V

• 50 V

• 250 V

• zero

A positively charged particle is released from rest in an uniform electric field. The electric potential energy of the charge

• remains a constant because the electric field is uniform

• increases because the charge moves along the electric field

• decreases because the charge moves along the electric field

• decreases because the charge moves opposite to the electric field

A parallel-plate capacitor has circular plates of radius 8 cm and plate separation 1 mm. What will be the charge on the plates if a potential difference of 100 V is applied?

• 1.78 × 10^–8 C

• 1.78 × 10^–5 C

• 4.3 × 10^4 C

• 2 × 10^–9 C

Capacitance between points A and B is

• 4 μF

• 12/7 μF

• 1/4 μF

• 7/12 μF