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Question: 1
What is meant by Density? What is its SI unit.
Answer: 1
1-81Density of substance is defined as the ratio of mass per unit volume.
Formula: D=m/v
Question: 2
What is meant by density
Answer: 2
2-81Density of a substances is define as The ratio of mass per unit volume
Question: 3
What is the working principle of hydraulic press.
Answer: 3
3-81Hydraulic press is a machine which is used to lift heavy objects. It works on the principle of Pascal' law.
Question: 4
What is meant by elasticity?
Answer: 4
4-81The property of a body to restore its original size and shape as deforming force ceases to act is called elasticity
Question: 5
State Pascal's law.
Answer: 5
5-81Pressure applied at any point of a liquid enclosed in a container, is transmitted without loss to all other parts of the liquid e.g. Hydraulic press
Question: 6
What is Hook's law? What is meant by elastic limit?
Answer: 6
6-81The strain produce in body is directly proportional to applied stress with in elastic limit.
Constant = Stress/Strain
Question: 7
Does there exist a fourth state of matter
Answer: 7
7-81Yes, Plasma is a fourth state of matter i.e At very high temperature, the collision between atoms and molecules tears off their electrons. Atoms become positive ions. This ionic state of matter is called plasma.
Question: 8
Define the term pressure.
Answer: 8
8-81the force acting normally per unit area on the surface of a body is called pressure.
Formula: P = F/A
Question: 9
Explain the principle of floatation?
Answer: 9
9-81A floating object displaces a fluid having weight equal to weight of the object e.g. submarine and ships float in sea.
Question: 10
State Archimedes principle.
Answer: 10
10-81When a body is totally and partially immersed in the liquid the upthrust on it equal to the weight of liquid it displaces. Upthrust of liquid = pgV
Question: 11
What is barometer?
Answer: 11
11-81The instrument which is used to measure the atmospheric pressure is called barometer.
Question: 12
Give three applications of Pascal's law.
Answer: 12
12-81Hydraulic brake system ii. Hydraulic jack iii. Hydraulic press
Question: 13
How Kinetic molecular model of matter is helpful in differentiating various states of matter
Answer: 13
13-81Matter is made of particles called molecules.
Molecules remain in continuous motion
Molecules attract each other.
Question: 14
Can we use a hydrometer to measure the density of milk
Answer: 14
14-81Yes, We can use hydrometer to measure the density of milk, hydrometer is a glass tube with a scale marked on its stem immersed in the milk to find the density of milk
Question: 15
What is meant by deforming force.
Answer: 15
15-81The applied force which changes the shape, length and volume of substance is called the deforming force.
Question: 16
What is meant by elasticity
Answer: 16
16-81The property of a body to restore its original size and shape as deforming force ceases to act is called elasticity
Question: 17
Define Young's modulus.
Answer: 17
17-81The ration of stress to tensile strain is called Young's modulus.
Formula: Young Modulus= Stress/Tensile strain
Question: 18
What is meant by deforming force
Answer: 18
18-81The applied force which changes the shape, length and volume of substance is called the deforming force
Question: 19
What is the working principle of hydraulic press
Answer: 19
19-81Hydraulic press is a machine which is used to lift heavy objects. It works on the principle of Pascal Law
Question: 20
Define Atmospheric pressure:
Answer: 20
20-81Pressure exerted by atmosphere in downward direction is called atmospheric pressure.
Question: 21
Define density and write down its mathematical form and unit
Answer: 21
21-81Density: Density of a substance is defined as its mass per unit volume unit of density is kilogram per cubic meter (kgm -3)
Density = mass of a substance / volume of that substance
Question: 22
Why woodmen block block float on water
Answer: 22
22-81A wooden block float on water because the weight of an equal volume of displaced water is greater than the weight of wooden block. An upthrust force acts upward
Question: 23
What is barometer
Answer: 23
23-81The instrument which is used to measure the atmospheric pressure is called barometer Mercury varmeter is used commonly to measure the atmospheric pressure.
Question: 24
Define Elastic Limit
Answer: 24
24-81The maximum stress which a body can bear without causing permanent deformation is called elastic limit.
Question: 25
What is a barometer
Answer: 25
25-81Barometer: An instrument used to measure the atmospheric pressure by determining the height of the mercury column known as barometer
Question: 26
Write two rules of oxidation number?
Answer: 26
26-81The oxidation number of all elements in the free state is zero
In ions, the algebraicsum of oxidation number equals the charge on the ion
Question: 27
State Archimedes principle
Answer: 27
27-81When a body is totally and partially immersed in the liquid the upthrust on it equal to the weight of liquid it displace. Upthrust of liquid
Question: 28
Define Atmosphere.
Answer: 28
28-81Earth surrounded by cover of air is called atmosphere.
Question: 29
What does it represent when the atmospheric pressure at a place falls suddenly
Answer: 29
29-81The atmospheric pressure at a place falls down suddenly represent the accompanied by rain and typhoon to occur in few hours time
Question: 30
Differentiate between strain and tensile srain.
Answer: 30
30-81Tensile strain: A comparison of a change caused by the stress with original length is called tensile strain. The ratio of change in length to original length is called tensile strain.
Question: 31
Differentiate between stree and strain
Answer: 31
31-81Stress: Force acting on unit area at surface of body is called stress
Formula: Stress=F/A
Question: 32
Why water is not suitable to be used in a barometer
Answer: 32
32-81Water is lighter than mercury To measure atmospheric pressure at sea level a glass tube more than 10m long is required to make a water barometer, which is difficult to a handle.
Question: 33
Difference between stress and strain
Answer: 33
33-81Stress: Force acting on unit area at surface of body is called stress.
formula: Stress = F/A
Unit ; It unit is Nm-2
Question: 34
Define pressure and write its formula.
Answer: 34
34-81Pressure : SI unit of pressure is Nn- 2 also called pascal (Pa).
The force acting normally per unit area on the surface of a body is called pressure.
Question: 35
Define elasticity and stress
Answer: 35
35-81Density: Density of a substance is defined as its mass per unit volume.
Unit: SI unit of density is kilogram per cubic metre
Question: 36
Define stress with its unit.
Answer: 36
36-81the force acting on unit area at the surface of the body is called stress.
Formula: sTress= F/A
Iti unit is Nm-2
Question: 37
What changes are expected if barometer reading shows a sudden increase
Answer: 37
37-81A rapid increase in atmospheric pressure means that it will soon be followed by a decrease in the atmospheric pressure indicating poor weather ahead.
Question: 38
It is easy to fill air in a balloon but it is difficult to remove air from a glass bottle.
Answer: 38
38-81It is easy to fill are in a balloon we can enter air until pressure inside the balloon is equal to the atmospheric pressure. But it is difficult to remove air from glass bottle because inside the glass bottle air pressure is low and atmospheric pressure is high
Question: 39
Why does atmospheric pressure vary with height
Answer: 39
39-81Air is a mixture of gases. The density of air in the atmospheric is not uniform. It decreases continuously as we go up Thats why the atmospheric pressure varies with height
Question: 40
What does it mean when the atmospheric pressure at place fall suddenly
Answer: 40
40-81When the atmospheric pressure at place falls suddenly it indicate the windy and showery condition it may rain or storm at this place
Question: 41
Define deforming force
Answer: 41
41-81The force which changes the dimension of the object such as length volume or which changes the shape of substance is known as deforming force
Question: 42
Give three applications of Pascal law
Answer: 42
42-81Hydraulic brake system
Hydraulic jack
Hydraulic press
Question: 43
What is Hook's law
Answer: 43
43-81The strain produce in body is directly proportional to applied stree with in elastic limit
Constant= stress/Strain
Question: 44
Write the application of Archimedes principles
Answer: 44
44-81Archimedes principle is used in designing ships and submarines. The floating of a big ship is based on Archimedes Principle.
Question: 45
Define the term pressure
Answer: 45
45-81The force acting normally per unit area on the surface of a body is called pressure
Question: 46
Why does the atmosp9heric pressure vary with height
Answer: 46
46-81Atmospheric pressure decrease with the increase of height Because as we move from sea level to at some height the density of air is going on the reduce.
Question: 47
Write some important features of kinetic molecular model of matter
Answer: 47
47-81Kinetic Molecular Model of Matter
Matter is made up of particles called molecules
The molecule's remain in continuous motion'
Molecules attract each other
Question: 48
What is meant by Reducing agent? Give examples.
Answer: 48
48-81The substance which help the reduction to occur are called reducing agents.
Examples:
1- Almost all metals are good raducals
2- CO, SO, H2, K1 are good reductants .
Question: 49
How does vacum cleaner work
Answer: 49
49-81The fan in a vacuum cleaner lowers air pressure in its bucket The air from outside enters into it quickly carrying dust particles. In this way dust particles are collected at the bottom of the bucket.
Question: 50
What is up thrust
Answer: 50
50-81Up thrust force: There is an up ward force which acts on an object kept inside a liquid This upward force acting on the object is called the up thrust force of the liquid
Question: 51
What is meant by Atmospheric pressure
Answer: 51
51-81Atmospheric Pressure: The pressure exerted by the gases that covers the Earth surrounding is called atmospheric pressure
Question: 52
Define stress and write its formula and unit.
Answer: 52
52-81Stress:
The force acting on unit area at the surface of a body is called stress
Stress = Force/Area = F/A
AI unit of stress is Nm-2
Question: 53
What makes a sucker pressed on a smooth wall sticks to it
Answer: 53
53-81Sucker pressed on a smooth wall due to atmospheric pressure Sucker pressed on a smooth wall sticks to it because sucker pump the air out In this way pressure outside the sucker is greater than inside of ti.
Question: 54
Show that atmosphere exerts pressure
Answer: 54
54-81The atmosphere of Earth consists of gases, vapor and dust particles. All these are material particles. Due to the force of gravity of these particles, they exert pressure. So any object inside the atmosphere experience pressure which is called the atmospheric pressure.
Question: 55
Write two differences between solid and gas stated of Matter
Answer: 55
55-81Gas: Gases have no fixed shape or volume They can be filled in any container of any shape
Their molecules havd randommotion and move random motion and move with very high velocities.
Gases are much lighter than solids
Air is example of gases.
Question: 56
Why does a piece of stone sink in water bt a ship with a huge
Answer: 56
56-81A piece of stone sink a in water because the upthrust displaced water is less than the weight of stone but in ship the upthrust of displace water is grater than the weight of ship that is why ship floats in water.
Question: 57
A wooden block floats on water why
Answer: 57
57-81A wooden block floats on water
Question: 58
Write one difference and one Similarity between ships and submarines
Answer: 58
58-81Ships: Ships can not travel under water
Ships can sink into the water
Sub marines: Submarines can travel under water
Submarines can not sink in to the water.
Question: 59
How the working of Hydraulic press?
Answer: 59
59-81The force F2 that acts on the larger piston is greater than the force Fq acting on the smaller piston. Hydraulic systems working in this way are known as force multipliers.
Question: 60
Define Young modulus
Answer: 60
60-81The ration of stress to tensile strain is called Young Modulus
Question: 61
What is upthrust
Answer: 61
61-81Upthrust: Upthrust is force act on a body upward when immersed in fluid is equal to the weight of dispaced water
Question: 62
What is meant by atmospheric ressure
Answer: 62
62-81Atmosphere: Earth surrounded by a cover of air called atmosphere
Question: 63
Define stress with its unit
Answer: 63
63-81The force acting on unit area at the surface of the body is called stress
Question: 64
How vacuumcleaner works?
Answer: 64
64-81All vacuum cleaner work on the same principle of creating negative pressure of creating negative pressure using a fan, trapping the sucked up dirt, cleaning exhaust air and then releasing it
Question: 65
Define matter and write name of its three states
Answer: 65
65-81Matter: Every thing that has weight and occupies some space is called matter
Question: 66
What is hydrometer
Answer: 66
66-81Hydrometer is a glass tube with a scale marked on its stem and heavyweight on the bottom It is use to measure density of fluid
Question: 67
What is atmospheric pressure? How can we measure the atmospheric pressure?
Answer: 67
67-81Atmospheric Pressure:
The earth is surrounded by a cover of air is called atmosphere . It extends to a few hundred kilometers above sea level. Just as certain sea creature live at the bottom of ocean , we live at the bottom of a huge ocean of air. Air is the mixture of gases.
The density of air in the atmosphere is not uniform . It decreases continuously as we go up.
Question: 68
Explain how a submarine moves up the waters surface and down into water
Answer: 68
68-81Submarine can also travel over and under water, when weight of water equal to its volume is greater than its weight. Submarine has a system of tanks. When tanks are filled of sea water, weight of submarine increases, As soon as weight of submarine become greater than upthrust of water, it dives into water and remains under water
Question: 69
Write two examples of Applications of Pascal law
Answer: 69
69-81Pascal's law find numerous applications in our daily life such as automobiles, hydraulic brake system, hydraulic jack hydraulic press and other hydraulic machines.
Question: 70
Write the term of pressure and write the factors on which it depends
Answer: 70
70-81Pressure: The force acting normally per unit area on the surface of a body is called pressure
Pressure depend on Pressure depend on the force and area of the surface
Question: 71
Can we use a hydrometer to measure the density of milk?
Answer: 71
71-81Question: 72
Why air become thinner and thinner as we go up
Answer: 72
72-81ir decrease with with height and force of gravity also decreases with height so air become thinner and thinner as we go up
Question: 73
Explain how a submarine moves up the water surface and down into water
Answer: 73
73-81Submarine floats over water when the weight of the water equal to its volume is greater than its weight Under this condition it is similar to a ship and remain partially above water level When the tanks of submarine are filled the weight of the submarine increases. As soon as its weight becomes greater than the upthrust, it dives into water and remains under water To comes up on the surface the tanks re emptied from seawater.
Question: 74
On what factors pressure of a liquid depends
Answer: 74
74-81The pressure of a liquid depends upon density and depth of liquid
Question: 75
State Hooke's law
Answer: 75
75-81Hooke's Law
The strain produced in a body by the stress applied to it stress within the elastic limit of the body
Question: 76
Define plasma
Answer: 76
76-81Plasma: At very high temperature the matter assumes the state of ions and electrons This state is called plasma This state is called plasma This is the fourth state of matter
In plasma gas occurs in its ionic state
Posititive ionis and electrons get separated in the presence of electric of magnetic fields in plasma
The neutral particals are also present in plasma
Its temperature is very high
Question: 77
Write two properties of liquids.
Answer: 77
77-81The distance between the molecules of liquid are more than in solids Thus attractive forces between them are ewaker
Like solids molecules of a liquid also vibrate about their mean position but are not rigidly held with each other
Liquid attains the shape of a container to which it is put Such as water attain the shape of that glass in which water.
Question: 78
State the principal of floatation Principal of Floatation:
Answer: 78
78-81A floating object displaces a fluid having weight equal to weight of the object.
Question: 79
On which principle ships and submarines float on surface of water and why
Answer: 79
79-81Ships and submarines float on surface of water on the principle of flotation It floats over water when the weight of water equal to its volume is greater than its weight
Question: 80
Why does a piece of stone sink in water but a ship with a huge weight floats.
Answer: 80
80-81Ships and boats float on water because the weight of an equal volume of water is greater than the weight of ships and boats. A stone sinks in water because the weight of an equal bolume of water is smaller than the weight of stone.
Question: 81
Which law is used in braking system of cars and buses
Answer: 81
81-81Law used in braking system of cars and buses
Pascals law is used in braking system of cars and buses.
