Length and Time

Length

Volume

Pendulum

Micrometer screw gauge:

Least count:  Least division on main scale/total number of divisions on circular scale

Total Value = Main scale reading + circular scale reading (Least Count)

Let’s look at a couple of examples:

Time:

Analogue and Digital devices:

• In analogue devices, the physical quantity is to be measured by using a pointer and scale system.
  • Negative values cannot be measured,
  • The range is small,
  • The uncertainty is half the least count.
• In digital devices, the physical quantities are to be measured by using a display with binary system.
  • The accuracy is high,
  • Both positive and negative values can be measured,
  • The range is large,
  • The uncertainty is the least count.

Time period (T)

• It is the time taken by an object to complete one oscillation.
• I unit is seconds (s)
• For example, if ‘t’ is the time taken by a pendulum to complete 20 oscillations then the time period would be
• 

Frequency (f)

• Number of oscillations completed by a particle or an object in 1 second
• 
• SI unit is rps (rotation per second) or Hertz (Hz), second inverse ()