Final answer:
Pressing combs can become negatively charged when run through hair due to the transfer of electrons. This can cause them to attract small pieces of paper due to static electricity, demonstrating the electric force in action.
Step-by-step explanation:
Pressing combs are usually made of materials like hard rubber or plastic. These materials can become electrically charged when rubbed against hair. This phenomenon is due to the transfer of electrons; the comb has excess electrons, and as it passes through hair, electrons move from the hair to the comb, creating a negative charge on the comb. This process is an example of triboelectric charging, which is a type of contact electrification.
When a student runs a comb through their hair and then brings it close to small pieces of paper, as described in an experiment, the charged comb will exhibit an electric force. According to observation and experimental evidence, the pieces of paper are attracted to the comb. This attraction occurs because the comb's excess electrons create a negative charge that induces a positive charge on the nearby pieces of paper, which are initially neutral.
The correct option regarding the behavior of the paper pieces in relation to the charged comb is 'b. Pieces of paper are attracted to the comb.' This attraction is a classic demonstration of static electricity, which is a fundamental concept in physics.