⊜ Toppers Study
Study Materials:
CBSE NOTES ⇒ Class 11th ⇒ Physics ⇒ Units and Measurement

## Units and Measurement

### Significant Figures

Rule for counting significant numbers

(2) In a whole number the zeros on the right side of the given number are non-significant.

45400 [significant number is 3]

(3) All the zeroes between two non –zeroes digit are significant.

Example: 21001 [significant number is 5]

200.0 --- significant number 3

(3) if the number is less than one the zero on right side of the decimal and to the left of non-zero digit are not significant.

0.00102    [significant number is 3]

0.000007  [significant number is 1]

2.00007   [significant number is 6]

Special rule

0.7    [significant number is 1]

0.70  [significant number is 2]

0.700 [significant number is 3]

Changing in unitary:

0.00003 = 3 × 10-5 [significant number is 1]

1.17 × 106 = [significant number is 3]

Accuracy indicates how close our measurement is to the true value.

Precision is measured by least count of the measuring instrument and it is indicated by number of significant figure in the value.

- Precising depends on significant number.

Example: if you have a wall clock having only hour and minutes hands and does not have second hand so it will not give pr�cising measure.

It is necessary that accuracy has precision no it is possible that if precise observation may not be accurate.

Rounding the numbers by significant numbers.

If digit to be dropped is 5 or 5 followed by zero then pr�cising digit will be increased by 1 and if it is odd. But there will be not changed if it will be even.

Actual Operation

Propagation of significant number in mathematical operation.

In result significant figure after decimal will be equal to minimum significant figures in any quantity that is added.

Example :

### Select Your CBSE Classes

Important Study materials for classes 06, 07, 08,09,10, 11 and 12. Like CBSE Notes, Notes for Science, Notes for maths, Notes for Social Science, Notes for Accountancy, Notes for Economics, Notes for political Science, Noes for History, Notes For Bussiness Study, Physical Educations, Sample Papers, Test Papers, Mock Test Papers, Support Materials and Books. Mathematics Class - 11th

NCERT Maths book for CBSE Students.

books

## Study Materials List:

##### CBSE NOTES ⇒ Class 11th ⇒ Physics
Physical world
Units and Measurement
Motion In A Straight Line
Motion In A Plane
Law of Motion
Work Energy and Power
Systems of Particles and Rotational Motion

New Books