Physics
Lightning is produced when

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

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Physics
Which one of the following is the correct sequence of passage of light in a compound microscope?

Eyepiece -Objective lens -Body tube -Mirror
Condenser -Objective lens -Body tube -Eyepiece
Condenser -Objective lens -Eye -piece -Body tube
Objective lens -Condenser -Body tube -Eye piece

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Physics
What is the principle of a ''Life Jacket"?

The person can sit on it like a raft
It increases the volume of the person to keep him afloat
It provides oxygen to a drowning person
It decreases the volume of the person to keep him afloat

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Physics
To resolve an object in an electron microscope,

Both A & B
None of these
The wavelength of the electrons must be close to the diameter of the object
The wavelength of the electrons must be greater than the diameter of the object.

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