Question

students in a science class were given a box of materials and asked to use the materials to demonstrate that moving charges can create a magnetic field. from the materials in the box, which can be used together to demonstrate the effect of moving charges?
a the battery, the magnet, and the voltmeter
b the battery, some wire, and the directional compass
c the voltmeter, some wire, and the directional compass
d the battery, the iron nail, and the directional compass

Explanation:

• The battery provides a source of electric current (moving charges).
• The wire allows the electric current to flow.
• The directional compass can detect the magnetic field created by the moving charges (electric current) in the wire. A compass needle will deflect when placed near a current - carrying wire, demonstrating that moving charges (current) create a magnetic field.
• Option A is incorrect because a magnet is not needed to show the effect of moving charges creating a magnetic field (we want to create the magnetic field from the current, not use an existing magnet). A voltmeter is also not relevant for demonstrating the magnetic field due to moving charges.
• Option C is incorrect because a voltmeter measures voltage and is not used to show the magnetic field from moving charges.
• Option D is incorrect because an iron nail is not necessary for demonstrating that moving charges create a magnetic field. The main elements are the source of current (battery), the conductor (wire), and the detector of the magnetic field (compass).

Answer:

B. The battery, some wire, and the directional compass