Physics
We always see the same face of the moon, because

It revolves on its axis in adirection opposite to that ofthe earth
It rotates at the same speed as the earth around the sun
It takes equal time for revolution around the earth and rotation on its own axis
It is smaller than the earth

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Physics
Lightning is produced when

Strong opposite charges in different clouds break down the resistance offered by the intervening air
Clouds strike against impurities in air and the friction burns up these impurities
Similar charges of electricity rush towards each other and then get repelled
Water vapour produces electricity in the clouds

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