The document discusses the concept of measurement errors, categorizing them into systematic and random errors, and highlights factors that cause inaccuracies such as instrumental and personal errors. It emphasizes methods to minimize these errors, including improved instruments and techniques, as well as taking multiple readings for better accuracy. Additionally, the document explains terms like least count, absolute error, and methods for calculating error percentages.

1. ERRORS IN MEASUREMENTS

2. ERROR
• The difference between the true value and the
measured value of a quantity is known as the
error of measurement.

3. ERROR
Systematic
Errors
Random
Errors

4. Systematic Errors
• Instrumental errors
zero error of instruments

5. Systematic Errors
• Instrumental errors
zero error of instruments

6. Instrumental errors
– Zero error of instruments
– Faulty instruments
Systematic Errors
Comparing instrument
with a standard one -
calibration

7. Systematic Errors
Error due to incorrect experimental
technique
–pressure,
–temperature,
–humidity, wind

8.  Instrumental errors
– Zero error of instruments
– Faulty instruments
Systematic Errors
Error due to incorrect experimental technique
– pressure,
– temperature,
– humidity, wind
Personal errors
– Parallax error,

9. Systematic Errors
Personal errors
– Parallax error,

10. Systematic Errors
Personal errors
– Parallax error
– Carelessness
– lack of proper setting of the
of apparatus

11. Instrumental errors
– Zero error of instruments
– Faulty instruments
Systematic Errors
Error due to incorrect experimental technique
 pressure,
 temperature,
 humidity, wind
Personal errors
– Parallax error
– Carelessness
– lack of proper setting of apparatus

12. METHODS TO REDUCE SYSTEMATIC ERRORS
• using better instruments,
• improving experimental techniques,
• avoiding personal mistakes.

13. ERROR
Systematic
Errors
Random
Errors

14. RANDOM ERRORS
• caused by unknown and unpredictable
changes in the experiment
Measuring blood pressure

15. METHODS TO REDUCE RANDOM ERRORS
• Taking more number of readings
• Take the average of all readings

16. Least Count Error
• The smallest value that can be measured by
a measuring instrument is called its least count.

17. Least Count
What is the length of this rod??????????
9cm
9.5cm
What is the least count of the scale?????????
1cm .5cm
.1cm

18. Vernier calliper Least Count= 1 MSD/No. of divisions of vernier
Least Count= .1cm/10
Least Count= .01cm

19. Screw gauge
Least Count= .001cm

20. Absolute error
• The measurement of length gives values of 2.54
cm, 2.51 cm, 2.48 cm, 2.55 cm, and 2.52cm.
5
52
.
2
55
.
2
48
.
2
51
.
2
54
.
2 




length
mean
cm
52
.
2

Absolute error 02
.
54
.
2
52
.
2
1 


a
mean
a

21. 5
0
03
.
04
.
01
.
02
. 




error
absolute
mean 02
.

mean
a

mean
mean
a
a
error
lative


Re
52
.
2
02
.

100



mean
mean
a
a
error
Percentage
008
.

100
008
. 
 0
0
8
.
