GATE Questions & Answers of Magnetic circuits

What is the Weightage of Magnetic circuits in GATE Exam?

Total 2 Questions have been asked from Magnetic circuits topic of Electromagnetic Fields subject in previous GATE papers. Average marks 1.50.

A transformer with toroidal core of permeability $ \mu $ is shown in the figure. Assuming uniform flux density across the circular core cross-section of radius $ r\ll\;R $ , and neglecting any leakage flux, the best estimate for the mean radius R is

 

A soft-iron toroid is concentric with a long straight conductor carrying a direct current I. If the relative permeability μr of soft-iron is 100, the ratio of the magnetic flux densities at two adjacent points located just inside and just outside the toroid, is _______.