Electrostatics Quiz

What is the study of stationary electric charges at rest called?

• Electrodynamics

• Electromagnetism

• Electrostatics

• Magnetostatics

Answer explanation

The study of stationary electric charges at rest is called electrostatics. It focuses on the forces and fields produced by these charges, distinguishing it from electrodynamics, which deals with moving charges.

Which instrument is used to detect the charge on a body?

• Voltmeter

• Galvanometer

• Ammeter

• Electroscope

Answer explanation

The electroscope is the correct instrument for detecting charge on a body. It visually indicates the presence of electric charge through the movement of its leaves, unlike the other instruments listed.

What is the dielectric strength of air?

• 60 x 10^6 V/m

• 10 x 10^6 V/m

• 3 x 10^6 V/m

• 30 x 10^6 V/m

Answer explanation

The dielectric strength of air is approximately 3 x 10^6 V/m. This value indicates the maximum electric field that air can withstand before breakdown occurs, making it the correct choice among the options.

What is the unit of surface charge density?

• Coulomb/meter

• Coulomb/meter^2

• Volt/meter

• Newton/meter

Answer explanation

Surface charge density is defined as charge per unit area. Therefore, its unit is Coulomb per square meter (C/m²), which corresponds to the choice 'Coulomb/meter^2'. The other options do not represent surface charge density.

What is the electric potential at a distance 'd' due to a point charge 'q'?

• V = (1/4πε₀)(d/q)

• V = q/d

• V = (1/4πε₀)(q/d)

• V = (1/4π)(q/d²)

Answer explanation

The electric potential V due to a point charge q at a distance d is given by V = (1/4πε₀)(q/d). This formula shows that potential is directly proportional to the charge and inversely proportional to the distance.

What is an equipotential surface?

• A surface with varying potential

• A surface with the same potential at all points

• A surface with maximum electric field

• A surface with no electric field

Answer explanation

An equipotential surface is defined as a surface where the potential is the same at all points. This means there is no potential difference, making the correct choice "A surface with the same potential at all points."

What happens to the electric field intensity inside a hollow charged sphere?

• It is maximum

• It varies with distance

• It is zero

• It is constant

Answer explanation

Inside a hollow charged sphere, the electric field intensity is zero due to the symmetry of the charge distribution. This means that any point within the sphere experiences no net electric field.

What is the relationship between electric field intensity and potential?

• E = V/d

• E = d/V

• E = V²/d

• E = d²/V

Answer explanation

The relationship between electric field intensity (E) and potential (V) is given by E = V/d, where d is the distance. This formula shows that the electric field intensity is directly proportional to the potential difference and inversely proportional to the distance.

What is the unit of energy in particle physics?

• Joule

• Electron Volt

• Coulomb

• Newton

Answer explanation

In particle physics, the electron volt (eV) is the standard unit of energy, particularly for subatomic particles. It represents the energy gained by an electron when accelerated through a potential difference of one volt.

What is the torque acting on an electric dipole in a uniform electric field?

• τ = qE

• τ = PE

• τ = P x E

• τ = E/q

Answer explanation

The torque (τ) on an electric dipole in a uniform electric field (E) is given by the cross product of the dipole moment (P) and the electric field, expressed as τ = P x E. This reflects the rotational effect of the field on the dipole.