can i replace a linear100k potentiometer with multi turn potentiometer 100k to get more resolution
Allow me to be a dissenting voice. Maybe not. Multi-turn pots are not inherently higher resolution than single turn pots of the same element length (and type), many merely contain a mechanism that may make it easier to set the wiper to a given position. The mechanism may have effects such as backlash that are annoying. 

Generally if you find yourself using only a small range of a pot, perhaps near one end, a better choice is to replace the unused part of the pot element with fixed resistors.

For example, if you had a 100K pot voltage divider with 5V applied and only used the first 1V of it you could add a series 80K resistor and shunt the element with 25K.

Some pots such as the 10-turn panel-mount Helipot wirewound style actually have a very long (helical) element and do give you greatly improved resolution, however it may still be worth considering limiting the range where appropriate.