At a depth of 50 m below sea level a human will experience a pressue of how many atmosphere

The pressure at a depth of 50 meters under the sea is 5 atm.

Explanation:

The pressure at the sea level is 1 atm.  When we go deeper into the sea the height of the water column increases and the pressure keeps increasing. The pressure increases by 1 atm after every 10 meters.

Therefore the pressure at 50 meter depth is 50/10  atm  which is 5 atm.

Any kind of organism living at greater depths in the ocean must adapt to the high pressure at the depths. Absence of air bladder in deep sea organisms is one such adaptation. Scuba divers also should use mechanisms to cope up with the high pressure at depths.