Why can one ignore quantisation of electric charge when dealing with macroscopic i.e., large scale charges?

What is the force of repulsion if each sphere is charged double the above amount, and the distance between them is halved?

An electrostatic field line is a continuous curve. That is, a field line cannot have sudden breaks. Why not?

Two large, thin metal plates are parallel and close to each other. On their inner faces, the plates have surface charge densities of opposite signs and of magnitude $17.0 \times 10^{-22}$ C/m$^2$. What is $E$: (c) between the plates?

Figure 1.30 shows tracks of three charged particles in a uniform electrostatic field. Give the signs of the three charges. Which particle has the highest charge to mass ratio?

Four point charges $q_A = 2 \mu C$, $q_B = -5 \mu C$, $q_C = 2 \mu C$, and $q_D = -5 \mu C$ are located at the corners of a square ABCD of side 10 cm. What is the force on a charge of $1 \mu C$ placed at the centre of the square?

Consider a uniform electric field $E = 3 \times 10^3 \hat{i}$ N/C. (a) What is the flux of this field through a square of 10 cm on a side whose plane is parallel to the yz plane?

Consider a uniform electric field $E = 3 \times 10^3 \hat{i}$ N/C. (b) What is the flux through the same square if the normal to its plane makes a $60^{\circ}$ angle with the x-axis?

The electrostatic force on a small sphere of charge $0.4 \mu C$ due to another small sphere of charge $-0.8 \mu C$ in air is 0.2 N. (a) What is the distance between the two spheres?

A polythene piece rubbed with wool is found to have a negative charge of $3 \times 10^{-7}$ C. (a) Estimate the number of electrons transferred (from which to which?)

Explain the meaning of the statement ‘electric charge of a body is quantised’.

An electric dipole with dipole moment $4 \times 10^{-9}$ C m is aligned at $30^{\circ}$ with the direction of a uniform electric field of magnitude $5 \times 10^4$ NC$^{-1}$. Calculate the magnitude of the torque acting on the dipole.

A point charge of $2.0 \mu C$ is at the centre of a cubic Gaussian surface 9.0 cm on edge. What is the net electric flux through the surface?

The electrostatic force on a small sphere of charge $0.4 \mu C$ due to another small sphere of charge $-0.8 \mu C$ in air is 0.2 N. (b) What is the force on the second sphere due to the first?

Two large, thin metal plates are parallel and close to each other. On their inner faces, the plates have surface charge densities of opposite signs and of magnitude $17.0 \times 10^{-22}$ C/m$^2$. What is $E$: (b) in the outer region of the second plate, and

A point charge causes an electric flux of $-1.0 \times 10^3$ Nm$^2$/C to pass through a spherical Gaussian surface of 10.0 cm radius centred on the charge. (a) If the radius of the Gaussian surface were doubled, how much flux would pass through the surface?

Two insulated charged copper spheres A and B have their centres separated by a distance of 50 cm. What is the mutual force of electrostatic repulsion if the charge on each is $6.5 \times 10^{-7}$ C? The radii of A and B are negligible compared to the distance of separation.

Check that the ratio $\frac{ke^2}{G m_e m_p}$ is dimensionless. Look up a Table of Physical Constants and determine the value of this ratio. What does the ratio signify?

A polythene piece rubbed with wool is found to have a negative charge of $3 \times 10^{-7}$ C. (b) Is there a transfer of mass from wool to polythene?

A point charge causes an electric flux of $-1.0 \times 10^3$ Nm$^2$/C to pass through a spherical Gaussian surface of 10.0 cm radius centred on the charge. (b) What is the value of the point charge?