EPO460 - Quiz for Video 2 (Magnetic Circuit)

Referring to this magnetic circuit, what is it called?

• Parallel magnetic circuit

• Series magnetic circuit

What is the unit for Magneto Motive Force (MMF)?

• Ampere-turn (At)

• Ampere-turn per meter (At/m)

Select the correct formula for 

 $\phi$  in a magnetic circuit.

•  $\phi=\frac{Force}{Reluc\tan ce}$  

•  $\phi=\frac{Reluc\tan ce}{Force}$  

An open circuit does not allow electrical current to flow

• True

• False

Determine the magnetic flux density of a magnetic pole having dimension 5 cm by 6 cm if the flux emerging from the pole is 2.7 mWb.

• 0.8 Tesla

• 0.9 Tesla

• 0.7 Tesla

• 0.6 Tesla

Determine the flux emerging from a magnetic pole having a cross-sectional area of   $0.196\ m^2$ , if the flux density is 1.8 Tesla 

• 353 mWb

• 354 mWb

• 355 mWb

• 356 mWb

Calculate the MMF is a current of 6 A is passed through a 1200-turn coil wound on a circular magnetic circuit

• 7000 At

• 7100 At

• 7200 At

Calculate the number of turns of a coil on a magnetic circuit if 300 At of MMF is produced when a current of 4 A is passed through it

• 70 turns

• 75 turns

• 80 turns

Find the magnetic field strength applied to the magnetic circuit of mean diameter 250 mm when a coil of 500 turns applied to it carries a current of 8 A.

• 5091 At/m

• 5092 At/m

• 5093 At/m

• 5094 At/m

Determine the reluctance of a piece of mild steel of length 100 mm and cross-sectional area1500 $mm^2$ when the relative permeability is 200.  

• 255.26  $\times10^3$  At/Wb

• 265.26 $\times10^3$   At/Wb

• 275.26 $\times10^3$  At/Wb

• 285.26 $\times10^3$  At/Wb