Question

The purpose of soft iron cylinder between the pole pieces of the horse-shoe magnet in a moving coil galvanometer is

• A. to increase the magnetic induction in the polar
  gap
• B. to evenly distribute the magnetic lines of force
• C. to provide a radial magnetic field
• D. to reduce the magnetic flux leakage in the polar
  gap

Answer 1

Answer: (A)

to increase the magnetic induction in the polar

gap
Soft iron cylinder is placed between the pole pieces of the horse-shoe magnet in a moving coil galvanometer to increase the magnetic induction in the polar gap. Soft iron is paramagnetic which increases magnetic induction when placed in field because atoms in soft iron align in such manner that it increases field.