An electrically neutral source is called an uncharged body or a neutral body. A neutral body is one that has an equal number of positive and negative charges so the net charge is zero. This results in no electrical force on other bodies in the vicinity.
Introduction
Electric charge is a fundamental property of matter that causes attraction and repulsion between objects. Objects can be positively charged, negatively charged, or neutral. Positively charged objects have a deficiency of electrons, while negatively charged objects have an excess of electrons. Neutral objects have an equal number of protons and electrons, so the positive and negative charges balance out.
Charged objects produce electric fields that exert forces on other charged objects. However, neutral objects with no net charge do not produce electric fields. This makes neutral objects safe to handle and unaffected by the electric fields of other charged objects nearby.
Understanding electrical neutrality is key to grasping several concepts in physics and chemistry. Let’s explore what makes an object electrically neutral, properties of neutral bodies, examples, and more.
What Makes an Object Electrically Neutral?
For an object to be electrically neutral, it must satisfy two conditions:
- The number of protons (positive charges) equals the number of electrons (negative charges).
- The electric field outside the object is zero.
Atoms and molecules are the building blocks of all matter. An atom has equal numbers of positively charged protons in its nucleus and negatively charged electrons orbiting the nucleus. With no net charge, atoms are electrically neutral.
Molecules are groups of atoms held together by chemical bonds. As long as a molecule has no missing or extra electrons, the positive and negative charges balance out, making molecules neutral.
Larger objects like rocks, plastic, wood, and air are made up of huge numbers of neutral atoms and molecules. With no net charge at the atomic level, the bulk material is also electrically neutral.
Properties of Electrically Neutral Objects
Neutral objects and materials exhibit the following properties:
- No net electrical charge
- No electric field produced outside the object
- Unaffected by external electric fields
- Do not exert electrical forces on other neutral or charged objects
- Can become charged by gaining or losing electrons
- Conductors can share and distribute charge
- Insulators resist flow of charge
With no external electric field, neutral objects remain electrically balanced. Charging only occurs by transferring electrons to or from the object. Conductors like metals can readily share and distribute charge. Insulators like glass resist charge flow and can become charged through friction.
Examples of Electrically Neutral Objects
Most everyday objects and materials are electrically neutral:
- Wood
- Plastic
- Glass
- Paper
- Water
- Air
- Soil
- Living organisms
- The human body
These objects are all composed of neutral atoms and molecules. They do not produce electric fields or exert forces unless they become charged in some way. Even conductors like metals are neutral until an imbalance of charge occurs.
Charging of Electrically Neutral Objects
Neutral objects can lose or gain electrons to become charged through:
- Friction from rubbing
- Contact with other charged objects
- Induction by an external electric field
- Electrical grounding
Rubbing certain materials like plastic causes electrons to transfer, resulting in static electricity. Touching a charged object allows electrons to flow until balance is achieved. External electric fields can polarize neutral objects and separate charges. Grounding connects an object to the earth to drain excess charge.
Neutralization of Charged Objects
There are several ways to neutralize or discharge charged objects:
- Connecting to ground
- Contact with a neutral object
- Exposure to ions of the opposite charge
- Electrical shorting
Grounding is the most common and safest way to discharge an object. Simply touching a charged object to a grounded metal surface allows excess electrons to safely flow away. Ions of the opposite charge supplied by anti-static devices can neutralize static cling. Shorting the excess charges together electrically also brings the object back to neutral.
Applications Involving Electrical Neutrality
The electrical neutrality of objects has many important applications including:
- Lightning rod grounding to neutralize charge buildup
- Antistatic devices to neutralize static electricity
- Electromagnetic shielding of neutral conductors
- Capacitors storing charge on neutral conductive plates
- Safety equipment for working near live power lines
In some cases, we want to maintain neutrality, like with static control when working with electronics. In other cases, we utilize charging and discharging principles, like with capacitor energy storage. Understanding electrical neutrality helps us control static buildup and discharge.
Conclusion
Electrical neutrality is an important concept underlying static electricity, charging, discharging, grounding, and other electrical principles. A neutral object contains an equal number of positive and negative charges with no net external electric field.
Most common materials are electrically neutral. They can become charged through contact, friction, induction, and grounding. The charges can then be neutralized through grounding, contact, ionization, or shorting. Mastering electrical neutrality aids both science and practical applications.
So in summary, an electrically neutral object is called an uncharged body or neutral body. Maintaining neutrality or utilizing charging and discharging underlies many key electrical technologies we use every day.
