A Comprehensive Guide to Home Security Systems:

 

Physical quantity:The characteristic of nature which can be measured in physical quantity.

Fundamental quantity (basic).

That properties of physics which can be expressed and measured in the term of magnitude and a unit is called fundamental quantity. This kind of physical quantity which do not depends on others physical quantities in doing of measurement.

1. Length:used for measuring distance (meter)
2. Mass : using for finding object state (kg)
3. Time:Using for measurement counting seconds or hours (sec).
4. Temperature: Using for measurement of heat capacity{{(Fahrenheit (°F),Celsius (°C) Kelvin (K)}}.
5. Electric current: Using for charge(Amper).
6. Amount of substance: Using for mole (mol/m3).
7. Luminous intensity: It is using for light capacity.(Candela).
8. Plane angle,Solid angle: It is using for finding angle Using  measurement of (π ).

Derived quantity:

That quantity which derived from the fundamental quantities is called quantities.

• The Current density = meter Ampere=m2A.
• The Magnetic field strength = Meter Ampere=mA.
• The Capacitance =Farad=F=VC=m−2 kg−1s4A2.
• The Pressure = Area Force=m2N.
• The Mass density= m3kg.
• The Specific volume = kg m 3

Unit:

The standard form which measurement for whole calculation in one

time.

characteristics: 

• The Volume should not change with time.
• Should not get destroyed with time.
• Must be reproduced whenever needed
• A should be of proper size .Neither too big  nor too short.