Question

When a positively charged rod is brought close to a neutral conductor without touching it, will the rod experience an attractive force, a repulsive force, or no force at all? Explain.

Short answer

Answer: The positively charged rod experiences an attractive force when brought near a neutral conductor without touching it. This is due to the redistribution of charges in the neutral conductor through the process of induction, which attracts the charged rod to the negatively charged side of the conductor.

Step-by-step solution

Understanding Induction

Induction is the process of redistributing the charges on a neutral object, due to the presence of a nearby charged object. When a positively charged rod is brought near a neutral conductor, the electrons in the conductor will be attracted towards the side of the conductor that is close to the charged rod, leaving the other side of the conductor positively charged.

Identifying the Forces

After the redistribution of charges due to induction, the side of the conductor near the charged rod will be negatively charged, while the opposite side will be positively charged. As opposite charges attract and like charges repel, the positively charged rod will experience an attractive force due to the negative charges on the nearby side of the conductor.

Conclusion

The positively charged rod will experience an attractive force when brought close to a neutral conductor without touching it. This is because of the redistribution of charges in the conductor through the process of induction, which results in attracting the charged rod towards the conductor.

Key concepts

Charge Redistribution

Charge redistribution is a fascinating process involving the movement of charges within or on the surface of a conductor, occurring as a response to nearby charged objects. This process is key to what is known as electrostatic induction. Imagine bringing a positively charged rod near a neutral conductor. You might expect nothing significant to happen, but instead, electrons within the conductor will start moving in response to the external charge.

These electrons, attracted by the positive rod's charge, gather on the surface of the conductor closest to the rod. This side becomes negatively charged due to the increased presence of electrons.

Meanwhile, the opposite side of the conductor loses some of these electrons, becoming positively charged. This separation of charge induces a polarity in the otherwise neutral conductor, showcasing how flexible and dynamic charges can be.

This concept of charge redistribution is fundamental in understanding how different objects interact with one another electrostatically, especially in certain electricity and magnetism experiments.

Conductors and Insulators

The world is full of materials, and when it comes to electrical charge, they can often be categorized as conductors or insulators. This classification affects how they behave under the influence of electric fields and is crucial in everyday applications.

• Conductors: These are materials that allow electrons to move freely. Metals like copper are excellent conductors. They permit charge redistribution easily when exposed to nearby electric fields or charged objects. That's why when a charged rod approaches a conductor, electrons within the conductor can swiftly relocate.
• Insulators: Unlike conductors, insulators do not allow free movement of electrons. Materials like rubber or glass hold their electrons tightly, preventing any noticeable charge redistribution. Thus, bringing a charged rod near an insulator wouldn't cause much change in the charge distribution within the insulator itself.

Bearing this in mind, knowing whether a material is a conductor or an insulator can heavily influence how it is used in electrical circuits or devices.

Attractive and Repulsive Forces

In electrostatics, forces between charged objects can be either attractive or repulsive. This is a fundamental aspect understood by studying electrostatic interactions.

When you have a charged object near another object, the type of force between them depends on the nature of their charges. Opposite charges, such as positive and negative, attract each other. When a positively charged rod is brought near a neutral conductor, the negative charges that gather on the conductor’s surface (due to charge redistribution) will create an attractive force towards the rod.

Conversely, like charges repel each other. Had the rod and the initial charge on the conductor been the same, they would push each other away. Understanding these forces helps to predict and explain behaviors in many physics experiments. It also aids in designing and working with electrical and electronic equipment, where controlling such forces is essential.