pHysics 2 exm 3

A loose spiral spring carrying no current is hung from a ceiling. When a switch is thrown so that a current exists in the spring, do the coils

Move closer together

Amperes law

The total magnetic field circulating around the closed loop path is equal/proportional to the electric current passing though that path

ferromagnetism

A small number of substances exhibit strong magnetic effects called_____. Some examples of ferromagnetic substances are iron, cobalt, nickel, gadolinium, and dysprosium. These substances contain permanent atomic magnetic moments that tend to align parallel to each other even in a weak external magnetic field. Th

Paramagnetic substances

have a weak magnetism resulting from the presence of atoms (or ions) that have permanent magnetic moments. These moments interact only weakly with one another and are randomly oriented in the absence of an external magnetic field.

Consider a solenoid that is very long compared with its radius. Of the following choices, what is the most effective way to increase the magnetic field in the interior of the solenoid?

overwrap the entire solenoid with an additional layer of current-carrying wire

What creates a magnetic field?

a moving object with electric charge and a stationary conductor carrying electric current

What happens to the field if the radius is doubled?

it is unchanged, it depends on the turns and current

What happens to the magnitude of the magnetic field inside a long solenoid if the current is doubled?

It become twice as large

What happens to the field if instead the length of the solenoid is doubled, with the number of turns remaining the same?

n=N/2l  which is 1/2. the original formula is N/length

Correctly describes Gauss's law for magnetism

The net magnetic flux through any closed surface is always zero because magnetic field lines form continuous closed loops.

A closed bowl with a flat lid (with area A) is placed in a magnetic field B, as shown in the figure. Which of the following statements correctly describes the magnetic flux, integral B. dA through the curved surface of the bowl?

BA