ET CH5: Magnetic

What is the right-hand thumb rule used for?

• Determining the direction of magnetic fields produced by a conductor

• Calculating the strength of magnetic fields

• Measuring the magnetic flux density

• Finding the permeability of a material

What is the unit of magnetic flux?

• Weber (Wb)

• Tesla (T)

• Ampere-turn (A-t)

• Gauss (G)

What is the relation between magnetic field intensity (H) and flux density (B)?

• B = φ/A

• B = μH

• B = Fm/l

• B = NI

What is hysteresis?

• The force required to remove the retentivity of a material

• The energy lost in the form of heat during a complete cycle of magnetization and demagnetization

• The lag of magnetic flux density behind the magnetic field strength

• The opposition to the establishment of a magnetic field in a material

What is the purpose of a solenoid?

• To remotely control a fluid in a pipe

• To open and close electrical contacts

• To measure magnetic flux density

• To generate mechanical motion from an electrical signal

What is the function of a relay?

• To remotely control a fluid in a pipe

• To open and close electrical contacts

• To measure magnetic flux density

• To generate electrical signal

What will happen when these magnets are brought close together?

• They will attract each other.

• They will repel each other.

• Nothing will occur.

• It will turn into one magnet.

The AREA around a magnet where you feel a pulling force.

• Gravity

• Magnetic Field

• Magnetism

• Current

The picture is an example of an:

• Electric grid

• Electromagnet

• Electric nail

• Electric power cell

Which diagram represents the direction of the magnetic field around a straight wire carrying a current out of the page?

• A

• B

• C

• D