What is a polar satellite? What is the orbital period of a polar satellite?

(N/A) polar satellite is a type of satellite that orbits the Earth in a north-south direction,passing over the poles,while the Earth rotates on its axis in an east-west direction.
These are low-altitude satellites,typically orbiting at a height of $h \approx 500$ to $800 \ km$ from the Earth's surface.
The orbital period of a polar satellite is approximately $100$ minutes,allowing it to cross any given latitude multiple times a day.
$A$ camera fixed on the satellite can view only small strips of the Earth in one orbit. Adjacent strips are viewed in subsequent orbits,effectively allowing the entire Earth to be scanned strip by strip throughout the day.
These satellites can observe polar and equatorial regions at close distances with high resolution.
Information gathered from such satellites is extremely useful for remote sensing,meteorology,and environmental studies of the Earth.