Page 12 - Introduction to Physics

ERROR

Error is uncertainty caused by measuring instrument or the observer or the physical factors

of the surroundings.

Systematic Error Random Error

 Caused by:
 Caused by: i. Surroundings factors, such as
i. Condition of the measuring instrument temperature and wind

ii. Condition of environment
ii. Carelessness of the observer
 Example  Example

zero error
i. ______________________________ i. Parallax error ii. Error in counting
ii. Inaccurate calibration iii. Natural errors (sudden change)

 Way of correction  Ways of correction
i. Proper calibration i. Take several readings and calculate

ii. Adjust the instrument frequently the average value.

Parallax Error

A parallax error is an error in reading an instrument because the observer’s eyes and pointer are
not in line / perpendicular to the plane of the scale.

How to avoid parallax error?
o
1. position of eyes must be in line/ perpendicular / 90 with the scale of the reading to be taken.
2. When taking reading from an ammeter, we must make sure that the eyes are exactly in front of
the pointer, so that the reflection of the pointer in the mirror is right behind the pointer. In other

words, the reflection of the pointer on the mirror could not be seen by the observer, then it is
free from parallax error. 12