Question

The magnitude of magnetic induction for a current carrying toroid of uniform cross-section is

• A. uniform over the whole cross-section
• B. maximum on the outer edge
• C. maximum on the inner edge
• D. maximum of the centre of cross-section

Answer 1

Answer: (A)

A toroid can be considered as a ring shaped closed solenoid. Hence, it is like an endless cylindrical solenoid.
Consider a torojd having n terms per unit length magnetic field at a point P in the figure is given as $\beta =\frac{{\mu }_{0}NI}{2\pi r}={\mu }_{0}nI$ Where, $n=\frac{N}{2\pi r}$ Hence, the magnitude of magnetic induction for a current carrying toroid of uniform cross-section is uniform over the whole cross-section.