Why Mosquitoes bite us? Fact File 26

Definitely, mosquitoes are annoying and they can spread diseases also. Since each mosquito lays thousands of eggs, destroying a mosquito equals destroying thousands of mosquitoes. Mosquitoes have chemo sensors which enable them to detect the humans or any other animal by the odor, heat etc released by the body and also the carbon dioxide exhaled by the humans and the other animals. Mosquito bites are caused only by the bite of a female mosquito. The female mosquito feeds off our blood by piercing the skin with the proboscis, a modified mouth part. While sucking our blood, mosquito deposits some saliva into the skin. The saliva contains anticoagulant proteins that remain in our body and react with the body chemicals, resulting in the characteristic itching and bump. Both Male and Female Mosquito are Plant juice feeders but female mosquito bites human beings to get blood protein for the maturation of their eggs. On the first day of emerging from the pupa, female mosquito do not bite and on the second day, it mates and starts feeding human blood. After two or three days it lays thousands of eggs in water and die off.
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How ELCB Prevents shock Hazard? Fact File 25

Earth Leakage Circuit Breaker (ELCB) is an automatic tripping switch that breaks the domestic power supply when it detects more than 25 milli ampere leakage current in the earth line. Earthing is provided in domestic power supply to drain leakage current to the earth if the phase line accidentally short with the metal body of the appliance. For this 3 pin plug is used in appliances. In the 3 pin plug, the earth pin is longer and larger than the other two pins. The longer earth pin first makes contact with socket so that if there is any leakage, the current will pass immediately through the earth line. The earth pin is larger in size to handle high current. If the ELCB is working well, it can immediately break the power supply to prevent shock hazard. It is necessary to confirm the working of ELCB occasionally by pressing its trigger switch.

ELCB is now called as GFCI (Ground Fault Circuit Interrupter). MCB is the Miniature Circuit Breaker used to break phase line, if a larger current passes through the wire. Tripping of MCB protects the wiring and connected appliances from damage.

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