Chapter.1 Measurements and experimentation

Question 1

Measurement

Answer 1

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

Question 2

Unit

Answer 2

The standard quantity used to measure and express the given physical quantity is called the UNIT.

Question 3

Unit

Answer 3

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

Question 4

Two parameters of the measurement of the physical quantity:

Answer 4

a) Unit

b) Numerical value

Question 5

Parameter Unit:

Parameter Numerical Value

Answer 5

The unit in which the quantity is being measured.

The numerical value which expresses how many times the above-selected unit contained in the given quantity

Question 6

Physical quantity =

Answer 6

Numerical Value x Unit

Question 7

CARS

Answer 7

1) The unit should be of convenient size
2) It should be possible to define the units without any ambiguity.
3) The unit should be reproducible
4) The unit should not change with space and time/The unit must always remain the same everywhere.

Question 8

Two Kinds of units

Answer 8

Fundamental unit

Derived unit

Question 9

Fundamental Unit

Answer 9

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.

Question 10

7 fundamental unit

2 complementary unit

Answer 10

MASS
LENGTH
TEMPERATURE
TIME
LUMINOUS INTENSITY
ELECTRIC CURRENT
AMOUNT OF SUBSTANCE
----------------------------------------
Angle 
Solid Angle

Question 11

MASS
LENGTH
TEMPERATURE
TIME
LUMINOUS INTENSITY
ELECTRIC CURRENT
AMOUNT OF SUBSTANCE
----------------------------------------
Angle 
Solid Angle

Answer 11

kg kilogram
m meter
K Kelvin
s seconds
cd candela
A Ampere
mol* mole
----------
rd radian
st-rd steradian

Question 12

Derived Units

Answer 12

Derived units are those which depend on the fundamental units or which can be expressed in the terms of fundamental units
example- AREA, VOLUME, SPEED, VELOCITY, ACCELERATION.

Question 13

What are the three fundamental units in mechanics?

Answer 13

MASS,LENGTH,TIME

Question 14

Three systems of unit

Answer 14

CGS
MKS
FPS

Question 15

CGS

Answer 15

IN CGS SYSTEM OF UNIT
Length is expressed in centimeters
Mass is expressed in grams
Time is expressed in seconds.
Also called as FRENCH SYSTEM OF UNIT

Question 16

MKS

Answer 16

IN MKS SYSTEMS OF UNIT
Length is expressed in meter
Mass is expressed in kilogram
Time is expressed in seconds
Also called as METRIC SYSTEM OF UNIT

Question 17

FPS

Answer 17

IN FPS SYSTEM OF UNIT
Length is measured in metres
Mass is measured in kilogram
Time is measured in Seconds
Also called as BRITISH SYSTEM OF UNIT.

Question 18

SI unit of length

Answer 18

METRE

Question 19

NON METRIC UNITS OF LENGTH

Answer 19

Astronomical unit
Light year-ly
Parsec-

Question 20

Astronomical unit

Answer 20

one astronomical unit is equal to the mean distance between the sun and the earth
1.496 x 10^11

Question 21

Light Year ly

Answer 21

a light year is the distance travelled by the light in vacuum in one year.
3x10^8 m/s x 365x24x3600
9.46 x 10^15m OR 9.46 x 10^12km

Question 22

SMALLER UNITS

Answer 22

Angstrom-separation and size of molecules

fermi- size of nucleus

Question 23

One gram is one thousandth part of kilogram

10^-3 kg

Answer 23

One milligram is 1 millionth part of kilogram

10^-6kg

Question 24

Quintal 100 kg

Answer 24

metric ton 1000kg or 10 quintal

Question 25

a.m.u atomic mass unit

u unified atomic mass unit

Answer 25

1/12th mass of one carbon-12 atom

Question 26

1 a.m.u

Answer 26

1.66 x 10^-27

Question 27

SOLAR MASS

Answer 27

The mass of large heavenly bodies is measured if terms of solar mass where 1 solar mass is the mass of the sun

Question 28

1 solar mass =

Answer 28

2 x 10^30 kg

Question 29

SI unit of time is second

Answer 29

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