PHYSICAL QUANTITIES
All quantities in term of which law of physics can be expressed and which can be measured directly or indirectly are called physical quantities.
Eg mass, length, time velocity etc.
Physical quantities are two types;
1 Fundamental quantities
2 Derived quantities
1 Fundamental quantities is that quantity which cannot be expressed in terms of any other physical quantity eg mass, length, time etc.
2 Derived quantities All the physical quantities which can be expressed in terms of fundamental quantities are called derived quantities eg;
Area =length *Breadth = length *length
Speed =distance /time = length /time
System of Fundamental Units
The following system of fundamental units use here;
1 CGS System(Centimeter gram second)
2 FPS System (Foot pound second)
3 MKS system (mass kilogram second)
4 SI System (System International)
MCQ
1 Which out of the following is a fundamental quantity?
1 velocity
2 Area
3 mass
4 Force
Ans 3rd
2 which of the following is not fundamental quantity?
1 angle of a plane
2 temperature
3 electric current
4 electronic charge
Ans 4th
3 which of the following is not a derived quantity?
1 force
2 surface tension
3 speed
4 angle
Ans 4th
4 which of the followingis not a system of units?
1 MKS
2 SI
3 CGS
4 FCS
Ans 4th
5 which of the following distances is comparable with thr length of your index finger?
1 10'-2
2 10cm
3 0.05m
4 0.005m
Ans 3rd
6 one nanaometer is equal to
1 10'9 cm
2 10'-6cm
3 10'-7cm
4 10'-9cm
Ans 3rd
7 one fermi equal
1 10'-6m
2 10'-8
3 10'-10m
4 10'-15m
Ans 4th
8 which of the following is not the unit of time?
1 light year
2 leap year
3 microsecond
4 lunar month
Ans 1st
9 which of the following represent value of 1 light year?
1 1.5*10^11 m
2 3.1*10^16 m
3 9.5*10^15 m
4 10^10 m
Ans 3rd
10 the suitable unit for measuring distance of sun earth is
1 merer
2 light year
3 kilometer
4 nautical mile
Ans 2nd
