Question

1. an electric current passing through a wire produces:

coldness

a magnetic field

decreased pressure

alternating current

direct current

Explanation:

To solve this, we analyze each option:

• "coldness": Current in a wire typically produces heat (Joule heating), not coldness. Eliminate.
• "a magnetic field": Oersted's discovery shows that an electric current through a wire creates a magnetic field. This is correct.
• "decreased pressure": Current in a wire has no direct relation to pressure decrease. Eliminate.
• "alternating current": The type of current (AC/DC) depends on the source, not just passing through a wire. Eliminate.
• "direct current": Similarly, the type of current is determined by the source, not the act of passing through a wire. Eliminate.

Answer:

B. a magnetic field