Electrostatic force
Explanation
The phenomenon described is a fundamental example of frictional electricity (triboelectricity) and electrostatic induction. It illustrates how a charged object can exert an attractive force on an uncharged, neutral object.
Detailed Analysis:
- Generation of Charge: When a plastic comb is rubbed with dry hair, electrons are transferred between the two surfaces due to friction. This results in the comb acquiring a net static electric charge.
- Polarization of Paper: When the charged comb is brought near neutral pieces of paper, its electric field induces a separation of charges within the paper molecules (dielectric polarization). The side of the paper closer to the comb develops a charge opposite to that of the comb, while the farther side develops a like charge.
- Net Electrostatic Force: Since the opposite charges are physically closer to the comb than the like charges, the attractive force dominates the repulsive force. This net attraction is the electrostatic force.
Analysis of Incorrect Options:
- Magnetic induction Magnetic induction: This phenomenon involves magnetic fields acting on ferromagnetic materials. Plastic and paper are non-magnetic materials.
- Gravitational attraction Gravitational attraction: While gravitational force exists between all masses, it is negligible in this context compared to the electrostatic force and is insufficient to lift the paper against Earth's gravity.
- Electromagnetic radiation Electromagnetic radiation: This refers to the emission and propagation of energy in the form of waves (e.g., light, radio waves) and does not explain the static attraction between objects.
Key Takeaway:
A charged body attracts a neutral body due to electrostatic induction, which creates a net electrostatic force strong enough to overcome the weight of light objects like paper.