Physics - ARJUNA SENANAYAKE

  Dimensions It is discusses three fundamental dimensions in physics. All other dimensions are formed by using these three fundamental dimensions. Basic dimensions – [Length] – L [Mass] – M [Time] – T (But it is having other additional dimensions also, Temperature –θ , Electric current – I, Intensity of light – L, number of moles – n)   If a physical quantity is given in square brackets, it represents a dimension of the quantity.   No dimensions for the quantities of units less. Examples : Index of refraction, strain, coefficient of friction, velocity ratio, efficiency, relative humidity, relative density Note: however the plane angle and solid angle has units, they do not have dimensions. The dimensions derived by using basic dimensions are called derived dimensions. Example 1: Dimension of velocity Example 2: Dimension of momentum   Example 3: Dimension of heat capacity. Example 4: Electric charge     ...

  MEASUREMENT Measurement and Measurement Units in Physics Measurement is a process of detecting an unknown physical quantity by using standard quantity.  For example : Take a book and use a ruler (scale) to find its length. Suppose the length was 20 cm. You underwent a process called  Measurement  where: ·          The unknown  physical quantity  was the length of the book. ·          The ruler was the  standard quantity . ·          20 was the  magnitude . ·          cm  was the  unit  of the book-length.   Units of Measurement Units provide specific meaning to the magnitude of a substance. Units of measurement provide a standard to identify the measurement of a physical quantify. Systems of Unit of Measurement There are differ...