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# Units and Measurements

Need for measurement: Units of measurement; systems of units; SI units, fundamental and derived units. Length, mass and time measurements; accuracy and precision of measuring instruments; errors in measurement; significant figures. Dimensions of physical quantities, dimensional analysis and its applications.

### Dimensions of Physical Quantities

The nature of physical quantities is described by its dimensions. All the physical quantities represented by derived units can be expressed in terms of...

### Significant Figures

Significant Figures: As discussed above, every measurement involves errors. Thus, the result of measurement should be reported in a way that indicates the precision...

### Combination of Errors

The combination of Errors: Error of A Sum or A Difference Error of A Product or A Quotient Error in case of a measured...

### Absolute, Relative, and Percentage Error

Arithmetic Mean or Average Value: Let the value obtained in n measurements are a1, a2, a3...., an. Then, the Arithmetic Mean or Average Value of...

### Accuracy, Precision and Errors

Error: The result of every measurement by any measuring instrument contains some uncertainty. This uncertainty is called error. Every calculated quantity which is based on...

### Measurement of Mass and Time

Measurement of Mass: Mass is a basic property of matter. It does not depend on the temperature, pressure or location of the object in space....

### Measurement of Length

Measurement of Length: You are already familiar with some direct methods for the measurement of length. For example, a meter scale is used for lengths from...

### Measurement, SI units and System of Units

The comparison of any physical quantity with its standard unit is called measurement. Physics is a quantitative science, based on measurement of physical quantities. Certain...