The emf induced in the rod is \(\underline{16}\) mV.
\(E = Blv\)
=\(4×10^{−3}×\frac{20}{100}×20\) \(Volts\)
= \(16\; mV\)
Which of the following graphs represent the variation of magnetic field \( B \) with perpendicular distance \( r \) from an infinitely long, straight conductor carrying current? 

The magnetic field is a field created by moving electric charges. It is a force field that exerts a force on materials such as iron when they are placed in its vicinity. Magnetic fields do not require a medium to propagate; they can even propagate in a vacuum. Magnetic field also referred to as a vector field, describes the magnetic influence on moving electric charges, magnetic materials, and electric currents.