Physical Quantities and Measurements
9th Class Physics Chapter 1 Exercise Short Questions with Answers
Q#1.2 : What is difference between base quantities and derived quantities . Give three examples in each case .
Q#1.3 : Pick out the base units in the following :
joule , newton , kilogramme , hertz , mole , ampere , metre , kelvin ,coulomb and watt .
Base Units :
Following are base unite :
Q#1.4 : Find the base quantities involved in each of the following derived quantities :
(a) speed :
- Derived from “Length and Time ”
(b) volume :
- Derived from “Length” .
(c) force :
- Derived from “Mass , Length and Time “.
(d) work :
- Derived from “Mass , Length and Time “.
Q#1.5 : Estimate your age in seconds .
|1 year =||365 days|
|1 day =||24 hours|
|1 hour =||60 minutes|
|1 minute =||60 second|
Total seconds in one year = ( 365 × 24 × 60 ×60 )
= 31536000 sec
- Suppose , your age is 17 years . So
Total seconds in 17 years = (31536000) × 17
= 536112000 sec
Q#1.6 : What role SI units have played in the development of science ?
- SI units have played very important role in the development of science and technology .
- Particularly this system is very useful to exchange the scientific and technical information.
Q#1.7 : What is meant by Vernier constant ?
Vernier Constant :
” It is ratio between smallest reading on main scale to the total divisions on Vernier scale .”
” The difference between one small division on main scale and one Vernier scale division .”
- The least count of Vernier caliper is called Vernier Constant .
- Least Count of Vernier caliper is 0.1 mm.
Q#1.8 : What do you understand by the zero error of a measuring instrument ?
Zero Error :
” If the zero of both the scales of a given instrument do not coincide with each other , it means the given instrument has zero error .”
” Any fault in the measuring instrument is called zero error of that instrument .”
- Zero error of Vernier Caliper .
- Zero error of Screw Gauge .
Q#1.9 : Why is the use of zero error necessary in a measuring instrument ?
It it necessary to find Zero Error of an instrument and apply Zero Correction .
- To get accurate measurement .
- To obtain an extreme correct value .
Q#1.10 : What is stopwatch ? What is the least count of a mechanical stopwatch you have used in the laboratories ?
” A device used to measure the time interval of an event .”
Least Count of Mechanical Stop-watch :
Mechanical stopwatches have least count upto 0.1 second .
Q#1.12 : What is meant by significant figures of a measurement ?
Significant Measurements :
” All the accurately known digits and the first doubtful digit in an expression are called significant figures .“
0.004080 has 4 significant figures.
Q#1.13 : How is precision related to the significant figures in a measured quantity?
- An improvement in the quality of measurement by using better instrument increases the significant figures in the measured results .
- The significant figures are accurately known digits and the first doubtful digit in an expression .
- → More number of significant figures → Measuring instrument has smaller value of its least count → Smaller the Least Count larger is the value of precision .
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Short Questions of Punjab Board , Last Five Year ,
Q : What is Physics ?
” The branch of science which deals with the study of matter and energy and relation between them .”
Q: Differentiate between Nuclear Physics and Atomic Physics .
|Nuclear Physics||Atomic Physics|
|It deals with the properties and behavior of nuclei and particles with nuclei .||It deals with the study of structure and properties of atom .|
Q : What is Electromagnetism ?
” The branch of physics which deals with the study of charges at rest and in motion , their effect and relation with magnetism is called electromagnetism .”
Q : Write two advantages of physics in our daily life ?
- A car is made on the principles of mechanics and refrigerator is based on the principle of thermodynamics .
- We use mobile phones which are based on principles of physics
Q : Define Physical Quantities ?
Q: What is meant by unit ?
Q: Define SI units ?
Q: Difference between base units and derived units ?
Q : What is term prefix ?
Q: Define Scientific notation ?
Q: What are measuring Instruments ?
Q : What is least count ?
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