I am using google map API version-3 , I was trying with different zoom value, I have randomly done for some numbers started with 1 upto 100 , map gets zoom in for increasing
The range depends on where you are looking at. Some places only have zoom levels of 15 or so, where as other places have 23 (or possibly more). Here are some examples of 23 zoom levels. Google Maps has a getMaxZoomAtLatLng API call you can make to retrieve the max zoom level.