Questions

The world’s largest tropical rainforest Amazon rain forests are called "Lungs of the Earth". It is so called because it produces 20% of the Earth's oxygen, and is also a vast carbon sink, absorbs more than 1 billion tons of atmospheric carbon which is emitted by the burning of fossil fuels annually.

There are 60 minutes in an hour.

In ¾ of an hour there are (60 × ¾) minutes = 45 minutes.

In ¾ of an hour there are (60 × 45) seconds = 2700 seconds.

Siren sounds for every 5 seconds.

In 2700 seconds = 2700/5 = 540 times.

The count start after the first sound, the Siren will sound 541 times in ¾ of an hour.

Volatile memory is computer memory that requires power to maintain the stored information. It is a temporary memeory which cannot contain information permanently.

Example :: RAM or Random Access Memory

(Maximum Cost Per Click) x (Quality Score)

Passivity of iron is due to formation of an extremely thin and impervious film of ferrosoferric oxide Fe3O4on the surface of iron. Chromic acid, being a powerful oxidising agent (like nitric acid ) renders iron passive.