Question

what will be atmospheric pressure at altitude where there is no air​

Answer 1

Answer:

Pressure decreases exponentially with altitude. The fraction of total atmospheric weight located above altitude z is P(z)/P(0). At 80 km altitude the atmospheric pressure is down to 0.01 hPa, meaning that 99.999% of the atmosphere is below that altitude.

Answer 2

Answer:

Atmospheric pressure decreases as the height of a surface above ground level increases. This is because, as the altitude increases: the number of air molecules decreases. the weight of the air decreases.