Assessment

What is magnetism?

• A phenomenon by which a material exerts either attractive or repulsive force on another.

• A property of materials that allows them to conduct electricity.

• The ability of a material to resist deformation.

• A measure of how much a material can be magnetized.

What is the basic source of magnetic force?

• Movement of electrically charged particles.

• The alignment of magnetic dipoles.

• The presence of unpaired electrons.

• The structure of the atomic nucleus.

What is the Bohr magneton?

• Magnetic moment due to spin of an electron.

• A measure of the strength of a magnetic field.

• The unit of magnetic flux density.

• A type of magnetic material.

Why are not all materials magnets?

• Due to Pauli exclusion rule and orbital moments canceling out.

• Because they do not have enough electrons.

• Only certain materials can be magnetized.

• Magnetism is only present at high temperatures.

What are magnetic dipoles?

• Small magnets composed of north and south poles.

• Materials that exhibit no magnetic properties.

• Electrons that are unpaired in their orbits.

• The force exerted by a magnetic field.

What is the formula for magnetic field strength?

• H = nI/l

• H = l/nI

• H = I/nl

• H = lI/n

What is diamagnetism?

• A very weak magnetic effect that exists only in the presence of an external field.

• A strong magnetic effect that persists without an external field.

• The ability of materials to retain magnetism.

• A type of magnetism that occurs in all materials.

What is paramagnetism?

• A slight magnetic effect that occurs in the presence of an external field.

• A strong magnetic effect that is permanent.

• The absence of any magnetic properties.

• A type of magnetism that occurs only at low temperatures.

What characterizes ferro-magnetism?

• Permanent magnetic moments even in the absence of an external field.

• Weak magnetism that only occurs in the presence of an external field.

• The ability to conduct electricity.

• The presence of unpaired electrons.

What is anti-ferro-magnetism?

• Dipoles line up in opposite directions, resulting in zero magnetization.

• Dipoles align in the same direction, creating strong magnetization.

• A type of magnetism that occurs only in certain metals.

• The ability of materials to become magnetic at high temperatures.