Question

Some equipotential surfaces of the magnetic scalar potential are shown in figure. Magnetic field at a point in the region is

• A. $10^{-4}\,T$
• B. $0.5\times 10^{-4}\,T$
• C. $2 \times 10^{-4}\, T$
• D. None of these

Answer 1

Answer: (C)

As is clear from figure

$\Delta V = \left(0.2 - 0.1\right) 10^{-4 }\,T\, m$
$\Delta x = x\, sin30^{\circ}= 0.1 \times \frac{1}{2}$
$\therefore \quad\left|B\right| = \frac{\Delta V}{\Delta x} = \frac{0.1 \times10^{-4}}{0.1/2}$
$ = 2 \times 10^{-4}\,T$