How do Vacuum Flasks keep things hot?

A vacuum flask keeps things hot for several hours because it stops heat from escaping as far as possible. It is designed to prevent heat loss. The silver walls of the container inside the flask reflect heat rays back into the container.

There is also a vacuum between the walls of the container to stop heat from flowing through the walls. The container is surrounded by an outer shell made up of insulating material that decreases the loss of heat. The flask, thus, loses very less heat and keeps hot for a long time.

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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...

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What is Vacuum Tube

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