Magnet

Magnet An object that is surrounded by a magnetic field and that has the property, either natural or induced, of attracting iron or steel. According to one Greek legend, the name magnet was taken from the shepherd Magnes who discovered the magnetic stone by accident when his staff was mysteriously attracted to the force of the stone. Another, and perhaps more believable, theory says that the word magnet came from a city in Asia Minor, called Magnesia, where many of these mysterious magnetic stones were found.

Different types of magnet

There are many different types of magnets. Permanent magnets, Temporary magnets and Electromagnets. A permanent magnet is a magnet that does not lose its magnet field. Temporary magnets are those which act like a permanent magnet when they are within a strong magnetic field, but lose their magnetism when the magnetic field disappears. Electro magnet are adjustable by changing the magnitude of the current flowing through the wire and by changing the direction of the current flow.

Electromagnetic induction

Electromagnetic induction is the production of an electromotive force (emf) in a conductor as a result of a changing magnetic field about the conductor. It was discovered in 1831 by Michael Faraday and independently by Joseph Henry. 1821 Faraday discovered electromagnetic rotation. After few years Faraday noticed that when he moved a permanent magnet in and out of a coil or a single loop of wire it induced an ElectroMotive Force or emf, in other words a Voltage, and therefore a current was produced.

Solenoids

A long straight coil of wire can be used to generate a nearly uniform magnetic field similar to that of a bar magnet. Such coils, called solenoids.

galvanometer

The galvanometer is used to measure very low currents, such as those in bridge circuits.The galvanometer consists of a coil of wire often rectangular, carrying the current to be measure-d.

Michael Faraday

Michael Faraday was one of the most prolific scientists of the 19th century. Michael Faraday, who came from a very poor family, became one of the greatest scientists in history. A British physicist and chemist, Faraday is best known for his discoveries of electromagnetic induction. his other most notable discoveries are Electromagnetic Rotation, Gas Liquefaction and Refrigeration, Discovery of Benzene, Laws of Electrolysis, Faraday Cage. The unit of electrical capacitance is named the farad in his honour, with the symbol F.

Difference between
ac and dc generator

A.C.Generator

Both AC and DC generators produce currents via electromagnetic induction. In AC generators, the coil through which the current flows is fixed.It have two commutators. It is used to power for smaller motors and electrical appliances at home. In AC generator uses slip ring and brush. Here does not use of commutator

D.C.Generator

DC generators, the coil through which the current flows rotates in a fixed field. The two ends of the coil attach to a commutator: different halves of a single, rotating split ring. Metal brushes connect these split rings to an external circuit. It have only one commutator. It is used for functional in supplying power to heavy motors.

Inductor

It is a passive two-terminal electrical component which resists changes in electric current passing through it. An inductor is a passive electronic component that stores energy in the form of a magnetic field. In its simplest form, an inductor consists of a wire loop or coi-l.

Deadly Diseases
in the World

Tuberculosis
Tuberculosis (TB) is a bacterial infection caused by Mycobacterium tuberculosis. It’s a treatable airborne bacterium. The bacteria that cause tuberculosis are spread from one person to another through tiny droplets released into the air This can happen when someone with the untreated, active form of tuberculosis coughs, speaks, sneezes, spits, laughs or sings. Doctors make a distinction between two kinds of tuberculosis infection latent and active.
1: Latent TB: TB bacteria can live in the body without making you sick. This is called latent TB. That means you don’t have any symptoms and you’re not contagious. But one day become active
2: Active TB disease: This means the germs multiply and can make you sick. You can spread the disease to others.

Respiratory Cancers
This class of diseases include lung, tracheal, and bronchial cancers. Respiratory cancers affect the lung, larynx, trachea, and bronchus and depending on the location of the cancer, the symptoms change and also the risks, incidence and survival outcomes differ accordingly. The main cause of these cancers are pollution by smoking, secondhand smoking, and other carcinogens as a waste byproduct.

HIV/AIDS
Human immunodeficiency virus (HIV) is a virus that attacks immune cells called CD4 cells, which are a type of T cell. HIV is different in structure from other retroviruses. It is composed of two copies of positive-sense single-stranded RNA that codes for the virus’s nine genes enclosed by a conical capsid composed of 2,000 copies of the viral protein p24. AIDS is caused by the Human Immunodeficiency Virus (HIV) which is transmitted through bodily fluids. It is spread by contact with certain bodily fluids of a person with HIV, most commonly during unprotected sex, through sharing injection drug equipment.

Diarrheal Diseases
Diarrheal diseases are a collection of diseases caused by multiple viral, bacterial, and parasitic organisms that share the common symptom of diarrhea, defined as the passage of three or more loose or liquid stools per day. Diarrhea is characterized by excreting fecal matter more than three times a day. Having diarrhea over the course of a few days depletes the body of water and salt. Each year Diarrheal disease kills around 525 000 children under five.

Chronic Obstructive Pulmonary Disease
Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory lung disease that causes obstructed airflow from the lungs. This disease affects the lungs, making it more difficult for the patient to breathe. The main cause of COPD is tobacco use, including second hand smoke.

Stroke
A stroke occurs when an artery supplying blood to the brain is blocked or leaked. A stroke is a medical condition in which poor blood flow to the brain results in cell death. The main risk factor for stroke is high blood pressure. Other risk factors include tobacco smoking, obesity, high blood cholesterol, diabetes mellitus, a previous TIA, and atrial fibrillation. A stroke may be caused by a blocked artery (ischemic stroke) or the leaking or bursting of a blood vessel (hemorrhagic stroke).

Coronary
Artery Disease

Coronary artery disease (CAD) is a condition where vessels supplying blood to the heart become narrowed. This is commonly caused by unhealthy dieting and smoking. Coronary artery disease develops when the major blood vessels that supply your heart with blood, oxygen and nutrients (coronary arteries) become damaged or diseased. The most common cause of CAD is vascular injury with cholesterol plaque buildup in the arteries, known as atherosclerosis. Reduced blood flow occurs when one or more of these arteries becomes partially or completely bloc-ke-d.