Thousands of people die of electric shocks all over the world, every year. Therefore, we must handle electric appliances with utmost care. For this, it is important that we understand the basic principles of electricity. Electricity flows more easily through metals like silver, copper, iron and aluminium. They are called good conductors of electricity. Materials like wood, glass, air, porcelain and rubber offer great resistance to its flow. They are called ‘insulators’ and are used to confine electricity to the conductors. They can be seen in the flexible cord used to connect the appliances to the plug on the switchboard. Due to wear, insulators deteriorate and can crack or peel off. Such a defective flexible cord is dangerous and you can get an electric shock from the exposed electric conductor. Such a cord must be immediately replaced. Only three wire cords should be used and good earth connections should be made. The third wire is to conduct the leakage of the current to the earth. Without the earth connection, there is a greater risk of an electric shock. How and why do we get an electric shock? Our body offers considerable resistance to electric current when it is dry. Dry skin offers 100 to 600 times more resistance than the wet skin. When we stand on an insulator like wood or rubber very little current can flow through the body but when we are wet and stand barefoot on the wet ground, as in a bathroom, greater amount of current can pass through our body. The severity of an electric shock depends on the rate of current that flows through the body. A current of about 0.1 ampere passing through a vital organ, like the heart, can be dangerous. The larger the amount of electric current and greater the duration of its passage, the more dangerous it is. As you perhaps know, electricity is of two types — Direct Current (DC) and Alternating Current (AC). In AC, the flow of current changes its direction 50 times in a second. If the duration is long enough, this can paralyse the muscles, tissues and nerves. Current passing through the body causes uncontrollable contraction of the muscles, which can halt breathing and cause an irregularity in heartbeat. These effects can lead to death. Heavy current destroys tissues, nerves and muscles due to heating. When we touch the two terminals of an electrical device with both hands, current passes through the heart. Hence, we should cultivate the habit of touching them only with one hand. We should also wear rubber-sole chappals or shoes while handling such devices. We should never touch a live wire or any object that is in contact with a live wire. Only an insulator like wood or rubber should be used to separate such wires or persons. In the case of an accident, the main switch should be switched off and artificial respiration should be given to the victim, till a doctor arrives. Electricity is a wonderful servant of mankind but it must be handled with care.
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