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##### Question: 1

Define Sound.

##### Answer: 1

1-143The branch of physics which deals with the physical aspects of sound waves, their production properties and applications.

##### Question: 2

Define Base Quantities.

##### Answer: 2

2-143Seven physical quantities which form the foundation for other physical quantities are called base quantities.

##### Question: 3

Define Mechanics.

##### Answer: 3

3-143It is the study of motion of objects its causes and effects.

##### Question: 4

What is international system of units?

##### Answer: 4

4-143A world-wide system of measurements is known as international system of units(SI).In SI,the units of seven base quantities are meter,kilogramme,second,ampere,kelvin,candela and mole.

##### Question: 5

Define physics.

##### Answer: 5

5-143Branch of science which deals with matter, energy and their mutual relationship. there are many branches of physics.

##### Question: 6

Define Derived Quantities.

##### Answer: 6

6-143The quantities that are expressed in terms of base quantities are called derived quantities.For Example speed area etc.

##### Question: 7

Define optics/light.

##### Answer: 7

7-143The branch of physics which deals with the study of physical aspect of light . Its properties working and use of optical instrument.

##### Question: 8

What role SI units have played in the development of science?

##### Answer: 8

8-143With the development in field of science and technology,the need for a commonly acceptable system of units was seriously felt all over the world particularly to exchange scientific and technical information.This need was fulfilled by SI units.

##### Question: 9

Define atomic physics.

##### Answer: 9

9-143Which deals with the study of structure and properties of atom.

##### Question: 10

Write twoi names of measuring instruments.

##### Answer: 10

10-143Names of measuring instruments are

##### Question: 11

Define electricity and magnetism.

##### Answer: 11

11-143The branch of physics which deals with the study of charges at rest and to motion their effects and their relationship with magnetism

##### Question: 12

When the zero error of screw gauge will be negative

##### Answer: 12

12-143Zero error of screw gauge will be negative if zero of circular scale has crossed the index line. In the case, the zero correction will be positive.

##### Question: 13

What are physical quantities.

##### Answer: 13

13-143All measurable quantities are called physical quantities. For example mass, length and temperature.

##### Question: 14

Define Heat.

##### Answer: 14

14-143Branch of physics which deals with the nature of heat, modes of transfer and effects of heat.

##### Question: 15

Define Plasma physics.

##### Answer: 15

15-143Which deals with the stydy of production properties of the ionic state of matter, the forth state of matter.

##### Question: 16

When the zero error of screw guage will be positive

##### Answer: 16

16-143Zero error will be positive if zero circular scale is behind the index line. In this case, mutiply the number of divisions of the circular scale that has not crossed the index line with the least count of screw gauge to find zero error,

##### Question: 17

What is least count of digital vernier callipers.

##### Answer: 17

17-143Digital vernier callipers has greater precision than mechanical vernier callipers. Least count of digital vernier calipers is 0.01 mm.MM.

##### Question: 18

What is Internal system of units?

##### Answer: 18

18-143The worldwide acceptable system of measurements is called international system of units. It was adopted in the 11th General conference on wight and measures held in Paris in 1960

##### Question: 19

Writer down rules to find the significant digits.

##### Answer: 19

19-143Rule to find the significant digits: Digits other than zero are always significant. i.e 27 has 2 significant digits and 275 has 3 significant digits

Zero between significant digits are also significant .e.g. 2705 has 4 significant digits.

Zeros after decimal point are significant. e.g 275.00 has 5 significant digits.

##### Question: 20

Waht do you understand by zero error of measuring instrument?

##### Answer: 20

20-143Zero error means the minimum error found in a measuring instrument.

##### Question: 21

Define physical balance.

##### Answer: 21

21-143A physical balance is used in laboratory to measure the mass of various objects by comparison. Its least count is 10 mg

##### Question: 22

Define least Count and also wirte least count of meter rod

##### Answer: 22

22-143Least Count: The smallest reading that can be taken by using any measuring instrument, is called its least count.

##### Question: 23

What is meant by vernier constant?

##### Answer: 23

23-143the vernier constant is defined as the difference between one main scale division and one vernier scale division

##### Question: 24

Why a Screw Gauge measures more accurately than Vernier Callipers

##### Answer: 24

24-143Least count of Vernier calipers is 0.1 mm and least count of screw gauge is 0.01mm. Thus measurements taken by micrometer screw gauge are the most precise.

##### Question: 25

Differentiate between base units and derived units.

##### Answer: 25

25-143Base units: The units that describe base quantities are called base units e.g. kg.

##### Question: 26

What is meant by Least Count of a screw gauge

##### Answer: 26

26-143Least count of screw gauge. The minimum measurement can measure a screw gauge is called least count of screw gauge.

##### Question: 27

What is nuclear physics.

##### Answer: 27

27-143Which deals with the properties and behaviour of nuclei and particles within the nuclei

##### Question: 28

Write two important parts of ernier callipers.

##### Answer: 28

28-143A vernier callipers consists on two parts. One part is main scale and other part is known as vernier scale. Main scale is attached with fixed jaw on which centimeters and millimeters are marked. The other part, vernier scale, is connected by a movable jaw which is divided into 10 equal divisions.

##### Question: 29

What is screw gauge, why is it used?

##### Answer: 29

29-143A screw gauge is an instrument used to measure small lengths with accuracy greater than a vernier callipers it is also called micrometer screw gauge.

##### Question: 30

Explain the construction and use of metre rule and measuring tape.

##### Answer: 30

30-143Metre rule is a length measuring instrument and is commonly used in laboratories to measure length of an object or distance between two points.

Construction: It is one metre long which is equal to 100 cm. Each centimetre is divided into 10 small divisions called millimeter (mm). Thus one millimeter is the smallest reading on metre rule.

##### Question: 31

What is meant by scientific notation.

##### Answer: 31

31-143A way of writing number s by using the power of ten or prefixes and there is only one nonzero digit before the decimal is called scientific notation. Example a number 62750 can be expressed as 6.275 x 10^4.

##### Question: 32

What is meant by Vernier Constant

##### Answer: 32

32-143The least count of the vernier callipers is also called the vernier constrant. Vernier callipers is a measuring instrument in which the difference between one small division on main scale division and one vernier scale division is 0.1 mm. It is called least count (LC)of the vernier callipers.

##### Question: 33

What are prefixes? Also give example.

##### Answer: 33

33-143There are some numbers which are very large or small .to write them using some suitable multiples or submultiples is called prefixes.
Example: Centi, Milli, mega

##### Question: 34

How is stop watch used

##### Answer: 34

34-143A mechanical stopwatch has a knob that is used to wind the spring that powers the watch.

This kind can also be used as a start-stop and reset button

The watch starts when the knob is pressed onece.

When pressed second time, it stops the watch

The third press brings the needle back to zero position.

##### Question: 35

Define geophysics.

##### Answer: 35

35-143Which deals with the study of internal structure of the earth.

##### Question: 36

What is meant by significant fique's

##### Answer: 36

36-143Significant figuers: All the digits that are known accurately and one estimated (doubtful) digit are called significant figures.

##### Question: 37

What is meant by pitch of screw gauge

##### Answer: 37

37-143A thimble has a threaded spindle inside it. As the tumble completes one rotation, the spindle moves 1 mm along the index line. The distance between consecutive threads on the spindle is 1mm. This distance is called pitch of screw gauge.

##### Question: 38

Differentiate between electronic balance and physical balance

##### Answer: 38

38-143Electronic balance: Electronic balance is the most precise instrument for the measurement of mass.

The least count of electronic balance is 0.001g or mg

##### Question: 39

Write four names of laboratory safety equipments.

##### Answer: 39

39-143A laboratory must have following safety equipments.

##### Question: 40

What is the use of physical balance

##### Answer: 40

40-143A physical balance is used in the laboratory to measure the mass of various objects by comparison.

##### Question: 41

How many divisions are there on vernier scale

##### Answer: 41

41-143Vernier scale having 10 divisions over is such that each of division is 0.9 mm.

##### Question: 42

How is precision related to the significant figures in a measured quantity

##### Answer: 42

42-143More significant figures mean greater precision. For example two students measure the length of a book 18.42 cm and 18.425cm respectively with a vernier calliper and screw gauge respectively. The measurement 18.425 =cm is more precision becasue it has greater significant figures/

##### Question: 43

How can we measure the volume of and irregular shaped solid

##### Answer: 43

43-143Take some water in a graduated measuring cylinder.

Note the volume vi of water in the cylinder.

Tie the solid with a thread

Lower the solid into the cylinder till it is fully immersed in water.

Note the volume vf of water

Volume of the solid will be vf-vi

##### Question: 44

Differentiate between positive zero Error and Negative zero Error

##### Answer: 44

44-143Positive Zero Error: Zero error will be positive if zero line of the vernier scale is on the right side of the zero the main scale.

##### Question: 45

What is Screw Gauge

##### Answer: 45

45-143Screw gauge: A screw gauge is an instrument that is used to measure small lengths with accuarc greater than vernier callipers. It is also called as micrometer screw gauge.

##### Question: 46

Find the number of significant figures in 0.00580km

##### Answer: 46

46-143Significant figures: 0.00580km the first two zero are not significant. They are used to space the decimal point. The digit 5,8 and the final zero are significant thus there are three significant figures.

##### Question: 47

What is the use of meter rod

##### Answer: 47

47-143A metre rod is a length measuring instrument which can use to measure the length of an object r distance between two points with an accuracy of 1min.

##### Question: 48

What are measuring instruments

##### Answer: 48

48-143Measuring Instruments: Measuring instrument are used to measure various physical quantities such as length, mass, time, volume etc. Measuring instruments used around 1300 AD were quite crude. On the other hand, digital clocks and watches used now-a-days are highly reliable and accurate.

##### Question: 49

What is the function of balancing screw in a physical balance

##### Answer: 49

49-143Balancing screws in a physical balance is used to bring the pointer at zero position.

##### Question: 50

What are prefixes

##### Answer: 50

50-143Prefixes: The words or letters added before a unit and stand for multiples or sub-multiples of that unit are known as prefixes.

##### Question: 51

How to use digital stop watch

##### Answer: 51

51-143The digital stop watch starts indicate the time lapsed as the start/stop button is pressed.

When start/stop button is pressed again, it stop and indicates the time interval recorded by it between start and stop of an event.

A reset button retroes its initial zero setting

##### Question: 52

Define physical quantities and explain its types

##### Answer: 52

52-143physical Quantities: All measurable quantities are called physical quantities.

Examples: length mass, time, temperature etc.

Characteristics: A physical quantity possesses at least two characteristics:

Numerical magnitude, A unit in which it is measured

##### Question: 53

Define measuring cylinder and write its uses

##### Answer: 53

53-143Measuring cylinder: A measuring Cylinder is a glass or transparent plastic cylinder. Measuring cylinder has a scale along its length that indicate the volume in mills lite

##### Question: 54

Write the use of prefixes

##### Answer: 54

54-143Some quantities are either very large or very small prefixes are used to express very large or very small quantities. It makes these quantities to be express and understand esaily.

##### Question: 55

What is the importance of physics in our daily life

##### Answer: 55

55-143Laws and principles of physics help us to understand nature.

The rapid progress in science during the recent years has become possible due to discoveries and inventions in the field of physics. The technologies are the applications of scientific principles. Most of the technologies of our modern society throughout the world are related to physics. For example, car is made on the principles of mechanics and a refrigerator is based on principles of thermodynamics. In our daily life there are lots of applications of physic For example in electrical appliances (air conditioners, washing machine), means of transport (cars, aeroplanes), means of communication (radio, T.V, Telephone) etc.

##### Question: 56

How do we need to measure extremely small intervals of time

##### Answer: 56

56-143In nature, there are so many phenomenon which vary with respect to the extremely small interval of time and for their experimental measurement we need to measure extremely small intervals of time.

##### Question: 57

What is electronic balance

##### Answer: 57

57-143Electronic balance is a device which is used to measure the mass of objects. It comes in different rangers i.e. mg, g,kg. Electronic balance is the most sensitive balance.

##### Question: 58

What is difference between base quantities and derived quantities also give example

##### Answer: 58

58-143Base Quantities: The quantities on the base of which other quantities are expressed are called base quantities.

Example: There are seven base quantities Length, mass, time, electric currrent, intensity of light, temperature, amount of substance.

##### Question: 59

What is digital stopwatch

##### Answer: 59

59-143Mechanical Stopwatch: A mechanical stopwatch can measure time interval upto minimum 0.1 second

A mechanical stopwatch showes reading through

During measuring reading may be a human error in reading

The least count of mechanical stopwatch is 0.1 second.

##### Question: 60

What is meant by significant figures of a measurement

##### Answer: 60

60-143In any measurement all accurately know digits and first doubtful digit are called significant figures.

##### Question: 61

Define scientific notation. Describe. it with examples.

##### Answer: 61

61-143Scientific Notation: In scientific notation a number is expressed as some power of ten multiplied by a number between 1 to 10 A simple but scientific way to write large or small numbers is to express them is some power of ten.

The Moon is 384000000 metres away from the Earth. Distance of the moon form the Earth can also be expressed as 3.84*10m. This form of expressing a number is called the standard form or scientific notation. This saves writing down or interpreting large numbers of zeros.

##### Question: 62

Define stop watch. What is L.C of mechanical stopwatch

##### Answer: 62

62-143The instrument used to calculate the time interval of an event is called stop watch. L.C of mechanical stopwatch = 0.1 second.

##### Question: 63

Find the number of significant figures in 100.8s and express in scientific notation

##### Answer: 63

63-143The number of significant figures in 100.8s is 4.

##### Question: 64

What do you understand by zero error of measuring instrument

##### Answer: 64

64-143Zero error means the minimum error found in a measuring instrument.

##### Question: 65

Define physics and explain its branches.

##### Answer: 65

65-143physics: The branch of science which deals with the study of matter, energy and their mutual relationship is called physics.

##### Question: 66

What is meant by scientific notation

##### Answer: 66

66-143A way of writing numbers by using the power of ten or prefixes and there is only one non-zero digit before the decimal is called scientific notation. For example a number can be expressed a similarly the standard form of.

##### Question: 67

Least count of vernier callipers.

##### Answer: 67

67-143The vernier constant is defined as the difference between one main scale division and one vernier scale division.

##### Question: 68

Define science and describe how science was divided into various branches.

##### Answer: 68

68-143The knowledge gained through observations and experimentations is called science. The word science is derived from the Latin word scientia" which means knowledge. Science was divided into various branches initially as described below.

##### Question: 69

Describe scientific notation? Give an example.

##### Answer: 69

69-143Scientific Notation:

In scientific notation a number is expressed as some power of ten multiplied by a number between 1 and 10. For example, a number 62750 can be expressed as 6.2750 x 10

^{4}##### Question: 70

Define unit and what is International system of units.

##### Answer: 70

70-143Unit: A standard quantity needed for measuring unknown quantities is called unit.

##### Question: 71

Define Scientific notation

##### Answer: 71

71-143Scientific notation: A way to express a given number as some power of ten multiplied or by prefixes by a number between is called scientific notation

between 1 and 10 is called scientific notation

##### Question: 72

Why do we study physics

##### Answer: 72

72-143Laws and principles of physics help us to understand nature Rapid progress in science during recent hears is due to discoveries and inventions in physics.

##### Question: 73

Write the numbers given in scientific notation.

##### Answer: 73

73-143In scientific notation.

0.0000000016g=1.6*10g

##### Question: 74

A chocolate wrapper is 6.7cm long and 5.4 cm wide. calculate its area up to reasonable number of significant figures.

##### Answer: 74

74-143Length of chocolate wrapper 6.7cm

##### Question: 75

What is meant by multiple and sub multiples

##### Answer: 75

75-143A unit can be increased or decreased by multiplying or dividing with 10 or some suitable power of 10.A positive power of 10 is called multiple and negative power of 10 is called sub multiples.

##### Question: 76

Why do we need to measure extremely small interval of time.

##### Answer: 76

76-143In physics most of the physical quantities are related to time like speed. velocity, acceleration etc. So to measure a quantity with great precision we need to measure extremly small interval of time.

##### Question: 77

Define nuclear physics

##### Answer: 77

77-143The branch of physics which deals with the properties and properties of atoms.

##### Question: 78

Give constructtion and use of a vernier Callipers

##### Answer: 78

78-143An accuracy greater than Imm can be obtained by using instruments such as Vernier Callipers.

An instrument which can length correct upto 0.1mm is called Vernier Calliper.

##### Question: 79

Define electricity and magnetism

##### Answer: 79

79-143The branch of physics which deals with the study of charges at rest and in motion, their effects and their relationship with magenetism

##### Question: 80

What role SI unit has play in the development of science

##### Answer: 80

80-143The SI unit are internationally acceptable units. They are very helpful to exchange scientific and technical information. They have brought consistency and uniformity in measurements and calculations by different scientist in different part of the world.

##### Question: 81

Define optics

##### Answer: 81

81-143The branch of physics which deals with the study of physical aspect of light Its properties. working and use of optical instruments.

##### Question: 82

Find the base quantities involved in each of the following derived quantities

##### Answer: 82

82-143speed, volume, force, work

##### Question: 83

Why is the use of zero error necessary in a measuring instrument

##### Answer: 83

83-143We use zero error in an instrument to get accurate reading.

##### Question: 84

Name the two scales of vernier calliper.

##### Answer: 84

84-143There are two scales in vernier callipers.

Main scale, Vernier scale

##### Question: 85

Pick out the base units in the following:

##### Answer: 85

85-143Base Unit: Kilogramme, mole, ampere, metre, Kelvin.

##### Question: 86

How numbers do are rounded off

##### Answer: 86

86-143There are some rules to round of the numbers.

If the last digit is less than 5, then if is simply dropped. For example 1.943 is rounded

If the last digit is greater than 5, then the digit on its left side is increased by one for example rounded

If the last digit is 5, then it is rounded to nearest even number. For example 1.35 is rounded to

##### Question: 87

Define Screw gauge.

##### Answer: 87

87-143Screw Guage:

Screw guage is an instrument used to measure small lengthswith occuracy greater than a vernier calliper. It is also called micrometer screw gauge

##### Question: 88

Define geo physics.

##### Answer: 88

88-143The branch of physics which deals with the study of internal structure of the earth.

##### Question: 89

What are the advantages of vernier calliper over meter rule

##### Answer: 89

89-143Vernier calliper can measure up to 0.1mm i.e up to one tenth of millimeter whereas meter rule can measure up to 1mm.

##### Question: 90

What is meant by prefixes

##### Answer: 90

90-143Prefixes: Prefixes are the words or letters added before a unit and stand for the multiples or submultiples of that unit

##### Question: 91

What is andromeda

##### Answer: 91

91-143Andromeda is one of the billions of galaxier nearest nearest to our mikly way galaxy.

##### Question: 92

What is significant figure?

##### Answer: 92

92-143Significant Figure:

All the accurately known digits and the first doubtful digit in an expression are called significant figures.

##### Question: 93

Estimate your 14 years age in seconds

##### Answer: 93

93-143total days in one year =14 years

Total days in 14 years 365 = dasys

= 14*365

=5110 days

##### Question: 94

Define sound

##### Answer: 94

94-143The branch of physics which deal with the physical aspects of sound waves their production properties and application

##### Question: 95

Define base quantities

##### Answer: 95

95-143Base Quantities: Base quantities are the quantities on the basis of which other quantities are expressed

##### Question: 96

What is international system of units

##### Answer: 96

96-143The worldwide acceptable system of measurments is called international system of units.It was adopted in the 11th General Conference on weight and measures held in paris in 1960

##### Question: 97

Define scientific notation and express 0.00580 in scientific notation.

##### Answer: 97

97-143Scientific notation: A way to express a given number as some power of ten mulltiplied or by prefixes by a number between 1 and 10 is called scientific notation.

Example: 0.00580

##### Question: 98

What do you mean by unit and system of unit

##### Answer: 98

98-143A standard quantity needed for measuring unknow quantities is know as unit

##### Question: 99

Enlist the main branches of physics.

##### Answer: 99

99-143Mechanic, Heat thermodynamics, Atomic physics, Nuclear physics . plasma physics, Light, sound, Geophysics, Electricity and magnetism.

##### Question: 100

Define atomic physic

##### Answer: 100

100-143The branch of physics which deals with the study structure and properties of atoms.

##### Question: 101

What is Hubble space telescope

##### Answer: 101

101-143Hubble space telescope orbits around earth. It provided information about astronomic planets and galaxies.

##### Question: 102

Differentiate between lever balance and electronic balance lever Balance:

##### Answer: 102

102-143 A lever balance consists of a system of levers. When lever is lifted placing the object in one pan and standard masses on the other pan, the pointer of the lever system mover.

##### Question: 103

Give characteristics of physical quantities.

##### Answer: 103

103-143There are two characteristics of physical quantities

A Physical quantities of have magnitude

A physical quantitites have a suitable unit in which it is measured

##### Question: 104

What is the function of balancing screws in a physical balance

##### Answer: 104

104-143Balancing screw are used to equalize the pans when the balance is empty.

##### Question: 105

Write down the formula to calculate the least count of screw gauge

##### Answer: 105

105-143Formula of least count is

least count=pitch of the screw gauge/no. of divisions on circular scale

##### Question: 106

What do you mean by zero error and zero correction?

##### Answer: 106

106-143Zero Error:

If the zero line of vernier scale is not coincidingwith main scale the zero error exits

##### Question: 107

Name five prefixes most commonly used.

##### Answer: 107

107-143There are prefixes most commonly used centi (c), milli. (m), kilo (k), mega (m), giga (g) micro (u)

##### Question: 108

Convert 12 years into seconds.

##### Answer: 108

108-143Days in one years = 365 days

##### Question: 109

Define physical balance

##### Answer: 109

109-143A physical balance is used in laboratory to measure the mass of varous objects by comparison Its least count is 10mg.

##### Question: 110

What role SI units have played in the development of science

##### Answer: 110

110-143With the development of science and technology S.I units fulfill the serious need of for a commonly accept system of unit all over the world

##### Question: 111

Define Kinemaics

##### Answer: 111

111-143Kinematics is the study of motion of an object without discussing the causes of motion.

##### Question: 112

Write in standard form 384000000m and 0.00045s.

##### Answer: 112

112-143384000000 m

##### Question: 113

Write the importance of physicsin our daily life

##### Answer: 113

113-143Physic plays an important role in our daily life For example, office equipments, electricity is widely used everywhere, domestic appliances machines used in industry etc. Work on the basic law and principles of physics.

##### Question: 114

Define least count of screw gauge

##### Answer: 114

114-143Least count of screw gauge can also be found by dividing pitch of screw on number of divisions on circular scale i.e. 0.01mm or 0.01cm

##### Question: 115

Why is the use of zero error necessary in a measuring instrument?

##### Answer: 115

115-143Zero error is necessary in measuring instruments because it helps us to check the instrument we are using wheather correct or wrong.

##### Question: 116

What is meant by pitch of screw gauge give its value

##### Answer: 116

116-143The distance between two consecutive threads on a spindle of a screw guge is called pitch Its value is 1mm.

##### Question: 117

Define the term light.

##### Answer: 117

117-143Light is the form of energy. Light is electromagnetic radiation that can be detected by the human eye. Light is a general term that is commonly used to refer to the visible spectrum. Visible means something that can be seen using the eye, as opposed to invisible" things that cannot be seen.

##### Question: 118

Describe two advantages of physics in daily life.

##### Answer: 118

118-143Pulleys that make it easy to left heavy loads.

##### Question: 119

What is important of physics in our daily life

##### Answer: 119

119-143The rapid progress in science during the recent yeard has become possible due to discoveries and inventions in the field of physics. For example, A car is made on the principles of mechanics and refrigerator is based on the principle of thermodynamics Similarly, the means of commuincation such as radio TV, Telephone, Computer are result of application of physics

##### Question: 120

Define prefixes and give examples.

##### Answer: 120

120-143Prefixes:

The words or letters added before a unit and stand for the multiples or sub-multiples of that unit are known as prefixes . For example Kilo, mega, milli , micro, etc.

##### Question: 121

What is screw gauge, why is it used

##### Answer: 121

121-143A screw gauge is an instrument used to measure small lengths with accuracy greater than a vernier callipers it is also called micrometer screw gauge

##### Question: 122

What is the difference between Biological sciences and physical sciences

##### Answer: 122

122-143Biological Sciences: The branch of natural philosophy in which we study about living things is called biological sciences.

##### Question: 123

Define the term light

##### Answer: 123

123-143Light is the form of energy Light is electromagnetic radiation that can be detected by the human eye Light is a general term that is commonly used to refer to the visible spectrum Visible means something that can be seen using the eye as opposed to invisible things that cannot be seen

##### Question: 124

What do you know aboutphysical balance?

##### Answer: 124

124-143Physical Balance:

Physical balance is a modified type of beam balance used to measure small masses by comparison with greater occuracy .

##### Question: 125

Writer the name of laboratory safety equipments.

##### Answer: 125

125-143The laboratory safety equipments are following

Waste disposal basket, Fire extinguisher, Fire alarm. First Aid box. Sand and water buckets, Fire blanket to put off fire.

##### Question: 126

Write 6000 km and 3800 km in standard form.

##### Answer: 126

126-143In standard form: 3800km=3.8*10km

##### Question: 127

Which one of following two instruments is more precise and why

##### Answer: 127

127-143Least count of vernier caallipers is 0.1 cm, and L.C of screw guage is 0.01mm so screw guage is more precise than vernier callipers because screw guage can take small reading more accurately.

##### Question: 128

What do you understand the by the zero error of measuring instrument.

##### Answer: 128

128-143- Any error in the measuring instrument that can effect the reading is called zero error
- Zero error may be positive or negative
- If the an instrument measured more then zero error will be positive
- If an instrument measured less then zero error will be negative
- The measured value will be less or more than the actual value

##### Question: 129

Define physics

##### Answer: 129

129-143Physics:

In physics, we study matter, energy and theirinteraction. The laws and principles of physics help us to understand

##### Question: 130

Write down the formula to calculate the least count of screw gauge.

##### Answer: 130

130-143Formula of least count is

##### Question: 131

Define zero error and zero correction.

##### Answer: 131

131-143Zero error If a measuring instrument does not measure the correct value of measurement, then this error is called zero error.

##### Question: 132

What is stopwatch? Write the least count of mechanical stopwatch

##### Answer: 132

132-143Stopwatch: stopwatch is an instrument which is use to measure time interval of an event.

##### Question: 133

What is law of conversation of momentum?

##### Answer: 133

133-143The momentum of an isolatedsystem of two or more than two interacting bodies remains constant

##### Question: 134

Define Physical quantities.

##### Answer: 134

134-143All measurable quantities are called physical quantities such as length,mass,time and temperature.

##### Question: 135

What is least count of digital Vernier calipers

##### Answer: 135

135-143Digital vernier callipers has greater precision than mechanical vernier callipers Least count of digital vernier callipers is 0.01mm

##### Question: 136

What is digital stopwatch.

##### Answer: 136

136-143Mechanical stopwatch: A mechanical stopwatch can measure a time interval up to minimum 0.1 second

A mechanical stopwatch shows reading through needles

During measuring reading may be a human error in reading

The least count of mechanical stopwatch is 0.1 second

##### Question: 137

Describe two situations in which force of friction is needed?

##### Answer: 137

137-1431-We cannot write if there would be no friction between pen and paper

2- Friction enables us to walk on the ground. we cannot run on a slippery ground. A slippery ground offers very less friction.

##### Question: 138

Why is the use of zero error necessary in a measuring

##### Answer: 138

138-143Zero error is necessary in measuring instrument to obtain an extremely correct value by means of applying zero correction.

##### Question: 139

Write down rules to find the significant digits

##### Answer: 139

139-143Rule to find the significant digits: Digits other than zero are always significant has 2 significant digits and 275 has 3 significant digits

Zero between significant digits are also significant e.g 2705 has 4 significant digits

Zero after decimal point are significance e,g 275.00 has significant digits

##### Question: 140

Estimate your age in seconds

##### Answer: 140

140-143Age in years= 15

Age in seconds=15 x 365 x24 x60x60

=473040000 second

##### Question: 141

What do you understand the by the zero error of measuring instrument

##### Answer: 141

141-143any error in the measuring instrument that can effect the reading is called zero error

##### Question: 142

Write four names of laboratory safety equipments

##### Answer: 142

142-143A laboratory must have following safety equipment's

- Waste disposal basket
- Fire extinguisher
- Fire alarm
- First aid box

##### Question: 143

What is meant by least count

##### Answer: 143

143-143The smallest reading that can be taken by using any measuring instrument is called its least count.