ELECTROMAGNETISM

THE MAGNETIC FIELD OF A MAGNETIZED IRON BAR WHEN STRONGLY HEATED

• BECOMES STRONGER

• BECOMES WEAKER

• REVERSES IN DIRECTIONS

• NO CHANGE

Reciprocal of reluctance is

• permeance

• susceptibility

• permeability

• reluctivity

The magnitude of induced emf in a conductor depends upon the

• the flux density of their magnetic field

• rate of change of flux linkage.

• amount of flux cut.

• amount of flux linkage.

Tesla is a unit of

• flux density

• field strength

• FLUX

• INDUCTANCE

The direction of magnetic lines of force is

• from south pole to north pole

• from one end of the magnet to another

• from north pole to south pole

• NONE OF THESE

The magnetic reluctance of a material

• does not vary with increasing cross-sectional area of material

• increases with an increasing cross-sectional area of material

• decreases with increasing cross-sectional area of material

• NONE OF THESE

Permeance is to reluctance as conductance is to

• INDUCTANCE

• RESISTANCE

• PERMEABILITY

• RESISTANCE

The electromagnet is made of

• STEEL CORE

• winding an insulated copper wire around a soft iron core

• soft iron core.

• COPPER WIRE

Which of the following is not a unit of flux?

• WEBER

• TESLA

• MAXWELL

The unit of relative permeability is

• it is dimensionless

• henry/metre

• henry/sq. m

• HENRY