What causes Aurorae?

The air is very thin and the stoms are scattered widely at a distance above 200 km from the Earth’s surface. Very small particles called electrons can peretrate the air at this height. If one such electron strikes an stom in the air it causes flash of light.

The glow produced by millions of such flashes it known as an aurora. The electrons that produce aurorae come from an invisible layer of electrons around the Earth known as Van Allen belt. The Sun activates these electrons to shoot down in the atmosphere. The electrons are attracted by the Earth’s magnetic field and are centered toward the north and south poles.

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How Many Type of Keys on a Keyboard?

Friends you know a keyboard is the most important part of a computer. It consists of different sets of keys that help us to enter information into the computer. Today we will discuss about keyboard and its keys types and use. A standard keyboard has 104 keys. Types of Keys in a Keyboard: Alphabet Keys Number Keys Special Keys Function Keys Navigation Keys 1. Alphabet Keys: 26 alphabet keys are present on a keyboard from A to Z. these keys are not present in the alphabetical order. These keys are used to type words, sentences or paragraphs. 2. Number Keys: These keys are used for typing numbers. These keys are present above the top row of the alphabet keys and also present on the right side of the keyboard. 3. Special Keys: Keyboard has more special keys such as Space bar Key, caps lock key, backspace key, shift key, enter key, symbol keys and tab key etc. 4. Function Keys: 12 function keys are present on a keyb...

Advantage and Disadvantage of Computer Generations

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What is Vacuum Tube

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