what would happen to timeperiod when the sattelite height is decreased?

Distance of a satellite from a planet is directly proportional to the time taken by it to complete one revolution. Therefore, if the height is decreased, the time period will also decrease.

V^2=GMe/(Re + h)

i.e velocity is inversely proportional to the distance from the earth. Hence, if h increases velocity decreases, and the time taken to complete one revolution increases.

T^2=k^2(Re + h) (k=4pi^2/square root of GMe) (square root of GMe is V)

So T is inversely proportional to V and directly proportional to h.

Time period also decreases...That's why polar satellites that orbit at around 1000 km height take only 1 hour to go around the Earth while geosynchronous ones take 24 hrs and are at a height of 36,000 kms..

When a satellite is made to revolve in a shorter orbit, the speed should be increased in order to maintain a stable orbital motion. This high speed and shorter orbit decreases the time period.

If the height of the satellite is decreased then, time period will also decrease.

Because T = 2π/R √(R+h)³/g

It gets shorter.

You really should try a few orbital radius and centripetal force for each radius so you know why. The math is not that hard.