A magnetic field exists around

Which of the following is a vector quantity?

A. Relative permeability

B. Magnetic field intensity

C. Flux density

D. Magnetic potential

What is the magneto-motive force (mmf) of a wire with 8 turns carrying three amperes of current?

A. 2,400 At

B. 240 At

C. 24 At

D. 2.4 At

Magnetism of a magnet can be destroyed by

A. heating

B. hammering

C. by inductive action of another magnet

D. by all above methods

Strength of an electromagnet can be increased by

A. increasing the cross-sectional area

B. increasing the number of turns

C. increasing current supply

D. all above methods