Physics
Waves that are required for long distance wireless communication are

Ultraviolet rays
Microwaves
Infrared rays
Radio waves

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Physics
Why two thin shirts can keep us warmer than a single thick shirt in winter ?

No radiation of heat takes place
Two thin shirts become thicker so prevent transmission of heat
Air layer between two shirts behaves like insulating media
Air layer between two shirts works as good conductor

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Physics
Skating on ice is possible because

The surface of ice is smooth
Ice is cold
The pressure on the ice due to skate melts the ice by lowering its melting point forming a thin film of water
The pressure on the ice due to skate raises its melting point

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