A ferromagnetic material is subjected to a strong magnetic field and afterward acts as a permanent magnet. Why does this occur?
The magnetic field aligns the magnetic domains mainly in one direction.
The magnetic field gives the ferromagnetic material an electric charge.
Long-range electric currents circulating in the iron make it magnetic.
The motion of the iron nuclei produces a magnetic field.
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With the simplified model of the eye, what corrective lens (specified by focal length as measured in air) would be needed to enable a person underwater to focus an infinitely distant object? (be careful-the focal length of a lens underwater is not the same as in air! assume that the corrective lens has a refractive index of 1.62 and that the lens is used in eyeglasses, not goggles, so there is water on both sides of the lens. assume that the eyeglasses are 1.90

The force needed to overcome static friction is usually less than that needed to overcome kinetic friction.true or false?

How many electrons in an atom could have these sets of quantum numbers? =3n=3 electronselectrons =4,ℓ=2n=4,ℓ=2 electronselectrons =6,ℓ=ℓ=−1n=6,ℓ=2,mℓ=−1