Chapter 1: Measurements and Units

numerical magnitude

It consists of a(n) ________ and a unit.

What are SI units?

SI units are set systematic international units, for measuring mass, time, and other base units and derived quantities.

Physical Quantity

It is a quantity that can be measured. It consists of a numerical value and a unit.

How can time intervals be measured?

Time intervals can be measured using a a stopwatch.

What is the use of Micrometer Screw Gauge?

It is used to measure objects that are too small to be measured with vernier calipers.

Define mass.

Mass is the measure of the amount of substance in an object.

What is the SI unit of mass?

SI unit of mass is kilogram (kg).

What is the SI unit of time?

SI unit of time is second (s).

What is the SI unit of length?

SI unit of length is metre (m).

What is the use of ruler?

They are used to measure small distances of a few centimetres (cm), with a precision of nearest millimetre (mm).

What is the use of micrometer?

It is used to measure objects that are too small to be measured with vernier calipers.

What is the use of vernier callipers?

It is a useful tool for measuring both internal and external diameters.

Define Volume.

It is the quantity of space an object takes up.

What is the SI unit of volume?

It's SI unit is cubic metre (m^3).

Define Density.

It is the quantity of mass per unit volume of a substance.

What is the formula and SI unit of density?

Formula is Density= Mass/Volume. Its SI unit is kilogram per cubic metre (kg m^-3).

How to measure volume of an irregular object?

If the shape of the object is too awkward to calculate its volume, then immerse the object in a measuring cylinder filled with water and then calculate the increase in water level. This value will be the volume of the object.