# Measurements and Experimentation Exe-1A Very Short Answer Physics Class-9 ICSE Selina Publishers

Measurements and Experimentation Exe-1A Very Short Answer Physics Class-9 ICSE Selina Publishers Solutions Chapter-1. Step By Step ICSE Selina Concise Solutions of Chapter-1 Measurements and Experimentation  with Exercise-1(A), Exercise-1(B) and Exercise-1(C) including Very Short Answer Type, Short Answer Type, Long Answer Type and Numerical Questions Solved . Visit official Website CISCE for detail information about ICSE Board Class-9.

## Measurements and Experimentation Exe-1A Very Short Answer Physics Class-9 ICSE Concise Selina Publishers

 Board ICSE Publications Selina Publication Subject Physics Class 9th Chapter-1 Measurements and Experimentation Book Name Concise Topics Solution of Exe-1(A) Very Short Answer Type Academic Session 2021-2022

## Measurements and Experimentation Physics Class-9 ICSE Concise Chapter-1

Note :-  Before Viewing Selina Concise Physics Solutions of Chapter-1 Measurements and Experimentation Class-9 . Read the whole chapter carefully and Solved all example with Numerical s of Exercise-1 Measurements and Experimentation Class-9.

#### Important Point for Measurement and Experimentation

International system of unit in  . Other commonly used system of unit- FPS and CGS ,Measurement using common instrument Vernier caliper ,  Micrometer and screw gauge for  length and simple pendulum for time .

Measurement of length using vernier caliper and micrometer screw gauge . least count leads count least to an increasing an accuracy least count in  Measurement and Experimentation , Vernier caliper  Screw gauge in Measurement and Experimentation.

### Measurements and Experimentation Class-9 Physics Solutions

Page 10

#### Question 1. What is meant by measurement?

Measurement is the process of comparing a given physical quantity with a known standard quantity of the same nature.

#### Question 2. What do you understand by the term unit?

Unit is a quantity of constant magnitude which is used to measure the magnitudes of other quantities of the same manner.

#### Question 3. How is a physical quantity expressed?

A physical quantity is expressed in terms of the following parameters:

1. The unit in which the quantity is being measured, and
2. The numerical value which expresses, how many times the above selected unit is contained in the given quantity.

Hence, the magnitude of physical quantity is expressed as : Physical quantity = (numerical value) x (unit)

#### Question 4. Name the three fundamental quantities.

S.I. unit of length (m): A metre was originally defined in 1889 as the distance between two marks drawn on a platinum-iridium (an alloy made of 90% platinum and 10% iridium) rod kept at 0°C in the International Bureau of Weights and Measures at serves near Paris.

and S.I. unit of mass (kg): In 1889, one kilogramme was defined as the mass of a cylindrical piece of a platinum-iridium alloy kept at International Bureau of Weights and Measures at serves near Paris.

while S.I. unit of time (s): A second is defined as 1/86400th part of a mean solar day, i.e.

1 s =  1/86400   × one mean solar day.

#### Question 5. What is the S.I. unit of Luminous intensity?

The S.I. unit of Luminous intensity is candela (cd).

#### Question 6. Define one parsec.

One parsec is the distance from where the semi major axis of orbit of earth (1 A.U.) subtends an angle of one second.

#### Question 7. Define a 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.

Example – Units of mass, length etc.

#### Question 8. Define a derived unit.

Derived units are those which depend on the fundamental units or which can be expressed in terms of fundamental units.

#### Question 9. Define standard metre.

A metre was originally defined in 1889 as the distance between two marks drawn on a platinum-iridium (an alloy with 90% platinum and 10% iridium) rod kept at 0oC in the International Bureau of Weights and Measures at serves near Paris.

#### Question 10. How is nanometer related to Angstrom ?

Relation between nanometer (nm) and Angstrom (Å) is expressed as:
1 nanometer = 10 Å

#### Question 11. Complete the following —

(a) 1 light year = ………..m

(b) 1 m   = ………..Å

(c) 1 m   = ………..µ (micron)

(d) 1 micron = ………..Å

(e) 1 fermi = ………..m

(a) 1 light year = 9.46 × 1015 m

(b) 1 m = 1010

(c) 1 m = 106 µ (micron)

(d) 1 micron = 104

(e) 1 fermi = 10-15 m

#### Question 12. Complete the following —

(a) 1g = ______kg

(b) 1mg = ________kg

(c) 1 quintal = ________kg

(d) 1 a.m.u (or u) = ________kg

(a) 1 g = 10-3 kg

(b) 1 mg = 10-6 kg

(c) 1 quintal = 100 kg

(d) 1 a.m.u (or u) = 1.66 x 10-27 kg

#### Question 13. What is a leap year?

A leap year is the year in which the month of February is of 29 days.

1 Leap year = 366 days

#### Question 14. The year 2020  will have February of 29 days’. Is this statement true?

Yes, the given statement is true.

#### Question 15. What is a lunar month?

One lunar month is the time in which the moon completes one revolution around the earth. A lunar month is made of nearly 4 weeks

#### Question 16. Complete the following

(a) 1 nanosecond =………s.

(b) 1 µs   =………s.

(c) 1 mean solar day =………s.

(d) 1 year = ………s.

(a) 1 nanosecond = 10-9 s

(b) 1 µs = 10-6 s

(c) 1 mean solar day = 86400 s

(d) 1 year = 3.15 × 107 s

#### Question 17. Name the physical quantities which are measured in the following units:

(a) u

(b) ly

(c) ns

(d) nm

(a) Mass

(b) Distance  (or length)

(c) Time

(d) Length

(a) Speed

(b) Force

(c) Work

(d) Pressure.

(a) ms-1

(b) kg ms-2

(c) kg m2s-2

(d) kg m-1s-2

(a) Newton

(b) Watt

(c) Joule

(d) Pascal.

(a) kg ms-2

(b) kg m2s-3

(c) kg m2s-2

(d) kg m-1s-2

#### Question 20. Name the physical quantities related to the following units:

(a) km2

(b) Newton

(c) Joule

(d) Pascal

(e) Watt

(a) Area

(b) Force

(c) Energy

(d) Pressure

(f) Power

—  : End of Measurements and Experimentation Exe-1A Very Short Answer Class-9 ICSE Physics Solutions :–

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