The pitch of a micrometer screw is 1/2mm &it’s least count is0.005mm find no. Divisions on the head scale

The screw gauge works on the following principle called the principle of screw:

When the  head of a screw gauge is rotated using the ratchet through one complete rotation, the distance moved by the screw for every complete rotation is constant. This constant distance moved by the screw for one complete rotation of head is called Pitch of the screw.If the head scale has n equal divisions, then the distance moved by the screw for even 1/n of a complete rotation can be measured accurately,this is called Least count of screw gauge.
Therefore Least count (L.C) = Pitch of screw / No. of divisions on head scale