Out of absolute error, relative error and fractional error which has unit and which has no unit?

Define fractional error.

Why strain has no unit?

Explain Absolute Error, Relative Error and Percentage Error.

What is called as relative error ?

Following observations were taken with a vernier callipers while measuring the length of a cylinder : 3.29 cm,3.28 cm,3.31 cm,3.28 cm,3.27 cm,3.29 cm,3.20 cm . Then find : (a) Most accurate length of the cylinder (b) Absolute error in each observation (c) Mean absolute error (d) Relative error (e) Percentage error Express the result in terms absolute error and percentage error.

Give an example of (a) a physical quantity which has a unit but no dimensions (b) a physical quantity which has neither unit nor dimensions (c) a constant which has a unit (d) a constant which has no unit.

Unit of relative density is

In an experiment, refractive index of glass wavs observed to be 1.54,1.53, 1.44, 1.54, 1.56 & 1.45, So, its absolute error, relative error & percentage error are ..... ........ & ...... Respectively.

Write a note on combination of error.