I can check whether an electromagnet is working by checking if it can repel insulators. (True/False)

Magnets are useful to separate broken wooden toothpicks from the good ones. (True/False)

The magnetic force becomes stronger when it attracts more iron nails. (True/False)

Keith had four nails of the same size but made of different materials (Plastic/Copper/Steel/Silver). She stroked each nail thrity times in the same direction with the same magnet. Which nail would attract some iron pins?

A magnet can be demagnetized by dropping it on the floor repeatedly. (True/False)

I can check whether an electromagnet is working by putting some paperclips near it. (True/False)

A bar magnet can attract all kinds of metal. (True/False)

Magnetism can pass through non-magnetic materials. (True/False)

I can check whether an electromagnet is working by checking to see whether it conducts heat easily. (True/False)

Magnetic force can only act at its poles. (True/False)

A magnet can be demagnetized by placing it under the sun for an hour. (True/False)

A magnet can be demagnetized by heating it over an open flame. (True/False)

When Magnet A is brought close to Magnet B, the two of them repel each other. What is a possible reason for this?