PhysicsKund Physics class 9 to 12 NCERT, JEE - NEET

Significant Fiqures in Algebraic Operations - Addition, Subtraction , Multiplication , Division  1. Addition or Subtraction operation: The sum of the quantities or difference between the quantities, the final result should retain the least decimal place as in the various numerical values.  Example :  12.32 + 100.004 = 112.324 = 112.32 ( after rounding off upto significant fiqures) 84.0 + 72.24 = 156.24 = 156.2  52.8 + 46.35 = 99.15  = 99.2 9.742-6.02 = 3.722 = 3.72 Question : A box is 2.3 Kg . Two coins of masses  20.15 g and 20.17 g are added to the box .  (a) What is the total mass of the box. (b) What is the difference in the masses of the coins to correct significant fiqures. Solution :  Total mass of box = 2.3 Kg + 0.02015 Kg + 0.02017 Kg = 2.34032 = 2.3 Kg round off upto. Difference = 20.17 - 20.15 = 0.02000 g ( 4 significant fiqures) 2. Multiplication or Division :  In multiplication or division of the numerical values, the final resul...

Rules of Rounding Off Significant Figures 1. If the digit to be dropped in a number is less than 5, then the preceding digit remains unchanged.  Example : 1.54 is rounded off to 1.5 , 8.64 is rounded off to 8.6. 2. If the digit to be dropped in a number is equal or greater than 5, then the preceding digit is raised by one.  Example : 2.49 is rounded off to 2.5 , 8.66 is rounded off to 8.7. 3. If the digit to be dropped is 5 or 5 followed by zero, then the preceding digit remains unchanged if it is even  Example : 3.65 is rounded off to 3.6 , 8.650 is rounded off to 8.6. 4. If the digit to be dropped in a number is 5 or 5 followed by zeros, then the preceding digit is raised by one, if it is odd. Example : 3.750 is rounded off to 3.8 , 8.750 is rounded off to 8.8 , 6.55 is rounded off to 6.6

Definition of Significant Figures : Significant figures (or significant digits) are the number of digits important to determine the accuracy and precision of measurement, such as length, mass, or volume. Significant digits in math convey the value of a number with accuracy. They are considered substantial figures that contribute to the precision of a number. Rules for Finding Significant Figures 1. All non-zeros digits are significant figures, e.g., 4362 m has 4 significant figures. 2. All zeros occuring between non-zero digits are significant figures, e.g., 1005 has 4 significant figures. 3. All zeros to the right of the last non-zero digit are not significant, e.g., 6250 has only 3 significant figures. 4. In a digit less than one, all zeros to the right of the decimal point and to the left of a non-zero digit are not significant, e.g., 0.00325 has only 3 significant figures. 5. All zeros to the right of a non-zero digit in the decimal part are significant, e.g., 1.4750 has 5 signific...

Notes NCERT Class 11 Physics Chapter 1 Units and Measurements - Physicskund Need for Measurement. Units of Measurement. Systems of Units, SI Units, Fundamental and Derived Units. Definition of Significant Figures and Rules for Finding Significant Figures. Significant Figures in Algebraic Operations. Rules of Rounding Off Significant Figures. Principle of Homogeneity. Dimensions of Physical Quantities. Dimensional Analysis and Its Applications.