[Physics Class Notes] on Electric Charge and Static Electricity Pdf for Exam

What is Static Electric Charge? 

Static electricity or static electric charge is the energy that is responsible for severe electronic damage, static explosions, and other hazards. A static electric charge is an imbalance between the electric charges in the body. This imbalance is brought about by various physical factors. A typical example of the production of a static electric charge is when two solid objects come into contact. One object gives up electrons and becomes positively charged while the other becomes more negatively charged. There is a loss and gain of electrons on either side. Static electric charge is the phenomenon responsible for lightning striking our planet, or the sudden jolt that we feel when we brush against someone’s arms.

Difference Between Static Electricity and Current Electricity 

The most significant and observant difference between static electric and current electricity is that in the case of static electricity, the charges are at rest and are accumulation on the insulator surface. On the other hand, in current electricity, the electrons are moving inside the conductor. The cause of static electricity is the movement of negative charges from one object to another. The cause behind current electricity is the movement of electrons. 

Static electricity can develop on both conductor and insulators, while current electricity develops only in the conductor. The time period of static electricity is very short, and it does not induce a magnetic field. Current electricity induces a magnetic field and exists for a very long period of time. 

Current electricity is measured by a digital and analog meter, while the gold leaf electroscope measures the static electricity magnitude. These are a few of the fundamental differences between static electric and current electricity.

What are the Biological Effects of Exposure to Static Electricity? 

Static electricity can’t harm the human body significantly. This is because the body is mainly composed of water, and water is not a good conductor of electricity. Depending on the weather, the effects and chances of being exposed to static electricity increases. Dry and cool temperature results in increased effects of static electricity. 

How to Avoid Static Electricity? 

There are several ways in which one can avoid static electricity nowadays. When rubbed on carpets, dryer sheets reduce the effects of static electricity more than you can imagine. It is advised to avoid rubber soles shoes because the static energy keeps building up whenever you walk on a wool surface such as a carpet or a doormat. Leather soles shoes will be a better option in such a case. 

Wool is the best conductor of static electricity. Even more than cotton, wool builds up quite a large amount of static energy. Avoid wearing wool during the dry season and replace it with cotton or something similar to it. 

Features of Static Electricity

• The charges must be at rest, or they should be stationary. 

• The charges generate electricity, which does not change with time, unlike current electricity. 

• The charges are held static as various forces work on them.

• Electric fields produced by static electricity are constant. There are no electric currents. 

• Using humidifiers, air ionizers reduce the effects of static electricity. 

• Allowing fresh air to enter or even opening a window for a day reduces static electricity generation. 

Solved Examples

1. Mention Some Static Electricity Examples. 

Static electricity has several uses and samples in the real world. A very innovative static electricity example is when we slide down a slide, all of our hairs stand up straight. This happens due to the friction caused as a result of the sliding. Positive charge reaches the end of each hair strand, and they end up standing straight. 

Another static electricity example is when we touch something metal, there is a small and quick spark which happens because the metal door is very conductive.  

Fun Facts About Static Electricity 

• One spark of static electricity can measure at least a thousand volts. The current lasts for only a short period of time, though.

• Lighting is the most potent and dangerous example of static electricity. 

• Although lightning is highly dangerous, about 70-80% of the people hit by a lightning bolt survive. 

• Static electricity builds up faster on a non-humid day. 

• A lightning bolt has a temperature of about 50,000 degrees F.