Ten questions. The result tells you which lessons you may skip.
Charges of \(2\,\mu\text{C}\) and \(-3\,\mu\text{C}\) are \(30\,\text{cm}\) apart. Take \(k = 9 \times 10^9\,\text{N m}^2/\text{C}^2\). The potential energy of the pair is
A particle is fired straight at a fixed like charge and gets to a distance \(d\). With twice the kinetic energy it gets to
A charge of \(2\,\mu\text{C}\) is moved slowly from a point at \(40\,\text{V}\) to a point at \(100\,\text{V}\). The work done by the electric field is
At the midpoint between \(+q\) and \(-q\),
A ring of radius \(R\) carries a charge \(Q\). At its centre,
Three charges of \(2\,\mu\text{C}\) sit at the corners of an equilateral triangle of side \(20\,\text{cm}\), with \(k = 9 \times 10^9\,\text{N m}^2/\text{C}^2\). The potential energy of the system is
The potential along the \(x\) axis is \(V = 5x + 3\) volts, with \(x\) in metres. The field is
A charge is carried round a closed path in the field of fixed charges. The total work done by the field is
The field of a short dipole at a distance \(r\) on its axis is \(E\). On its equatorial line at the same distance the field is
A dipole in a uniform field is in stable equilibrium when \(\vec p\) makes an angle with \(\vec E\) of