The atmospheric pressure at earth surface is P₁ and inside mine is P₂. They are related as:

1. P₁ = P₂
2. P₁ > P₂
3. P₁ < P₂
4. P₂ = 0

Nose bleeding occurs at high altitudes because :

1. the blood pressure becomes less than the atmospheric pressure
2. the blood pressure becomes equal to the atmospheric pressure
3. the blood pressure becomes more than the atmospheric pressure
4. not related with atmospheric pressure.

A barometer is used :

1. to measure atmospheric pressure
2. for weather forecasting
3. as an altimeter to measure heights
4. all of the above

At the summit of Mount Everest, the atmospheric pressure is :

1. only 40% of the atmospheric pressure at sea level
2. only 60% of the atmospheric pressure at sea level
3. only 30% of the atmospheric pressure at sea level
4. only 50% of the atmospheric pressure at sea level