Question

question #1
during an experiment, a student wraps a metal wire around a nail and connects the wire to a battery. when they moves the wire and nail over iron filings and pieces of paper, the student observes that the filings of iron are attracted to the nail.
what happens when the student disconnects the wire from the battery?
a the iron filings fall down, away from the nail.
b the pieces of paper are attracted to the nail.
c the pieces of paper are repelled from the nail.
d the iron filings remain attracted to the nail.
question #2
a horseshoe magnet is bent so that the north (n) magnetic pole is directly across from the south (s) magnetic pole.
which investigation demonstrates a non - contact force?
a place a nonmetallic object near the horseshoe magnet, and observe that the object does not move.
b place a metal object on the horseshoe magnet, and observe that the object remains in place when the magnet is picked up.
c place a metal object near the horseshoe magnet, and observe that the object moves toward the magnet.
d place a nonmetallic object on the south pole of the horseshoe magnet, and observe that the object does not move to the north pole of the magnet.

Explanation:

Question #1

When the wire is connected to the battery, the nail becomes an electromagnet (due to electric current in the wire). When the wire is disconnected, the electric current stops. An electromagnet requires an electric current to have magnetic properties. Iron filings were attracted due to the electromagnetism (when current was on). Without current (after disconnection), the nail no longer acts as an electromagnet. Paper is not magnetic (so options B and C are wrong as they involve paper - related magnetic interactions which don't happen). Option D is wrong because without the current (electromagnetism source gone), the iron filings won't be attracted.

A non - contact force is a force that acts at a distance without physical contact.

• Option A: A non - metallic object not moving near a magnet - there is no force (magnetic force acts on magnetic/metallic objects in general here, non - metallic object is not affected, but this doesn't demonstrate a non - contact force).
• Option B: A metal object on a magnet - there is physical contact (so it's not a non - contact force demonstration).
• Option C: A metal object near (not in contact with) a magnet moves towards it. This shows a magnetic force (a non - contact force) acting on the metal object.
• Option D: A non - metallic object on a magnet - no relevant non - contact force (as non - metallic object is not affected by magnetism in the way shown here, and it's on the magnet which is contact).

Answer:

A. The iron filings fall down, away from the nail.

Question #2