Errors in Measurements

Parallax Errors

-a parallax errors is an error in reading an instrument because the observer's eye and pointer are not in line perpendicular to the plane of the scale
-to avoid parallax error?
*the position of the eye must be in the line with the readings to be taken
*to overcome parallax errors in instruments with the scale and pointer,often have a mirror behind the pointer.The correct reading is obtained by making sure that the eye is exactly in front of the pointer,so that the reflection of the ponter in the mirror is behind it.