# Physical Quantities and Their Measurements

Who invented the electric battery?

Alexander Volta invented an electric battery

According to Newton’s concept of time and space, how is our universe
built?

According to Newton’s concept of time and space our universe is built in three
dimensions.

What are fundamental quantities?

The quantities that are independent and neutral, and do not depend on any
other quantity rather other quantities depend on them, are called fundamental
quantities.

What is fundamental unit?

A fundamental unit is that which is independent of any other unit or which can
neither be changed nor can be related to any other fundamental unit.

Physical Quantities and Their Measurement

What is dimension?

The power of fundamental quantities in a physical quantity is called its
dimension.

Measuring Instrument

What is meter scale?

The scale used to measure small lengths (100 cm or 1 m) is called meter
scale.

What is Vernier constant?

The difference between the smallest main scale division and the vernier
scale division is called the vernier constant.

What is screw pitch?

The displacement after one unit rotation of the circular scale that is the
length moved along the linear scale that length is called the screw pitch.

What is least count of a screw gauge?

If the circular scale is rotated only one division the distance that the
screw covers for that one rotation is said to be least count of the screw
gauge.

When one unit of the circular scale of a screw gauge is rotated, the length
moved by the edge of the circular scale along its linear scale is called the
least count of the screw gauge.

Error and Accuracy

What is an instrumental error?

The instrumental error refers to the error of a measuring instrument or the
difference between the actual value and the value indicated by the
instrument.

What is observational error?

The error caused by the operator while taking measurements is called
observational error.

What is absolute error?

The difference of the measured value with respect to the actual value is
called the absolute error.