9th Class Physics Chapter 6 Short Questions with Answers Solved

Question: 1

Define potential energy, also give its formula.

Answer: 1

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The energy possessed by a body due to to position is called potential energy. There are two type of potential energy. . Formula: P.E. = mgh i. Elastic potential energy ii.Gravitational potential energy.

Question: 2

Define Kinetic energy, also give its formula.

Answer: 2

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The energy possessed by a body due to its motion is called kinetic energy . Formula: K.E.=1/2 mv2

Question: 3

What is meant by term power?

Answer: 3

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The rate of doing work is called power. P = Work/time

Question: 4

Define watt.

Answer: 4

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The SI unit of power is watt, One watt is power of a device which does 1 J of work in 1 sec. 1 Watt = 1 Js-1

Question: 5

Define work. What is its SI unit.

Answer: 5

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Work: work is done when a force acting on a body displaces it in the direction it in the direction of force. W = Force x displacement w= F.S Unit: Its unit is newton meter or joule.

Question: 6

Define gravitational potential energy.

Answer: 6

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Gravitational potential energy possessed due to height of the body is called gravitational potential energy. G.P.E.= mgh Example: The energy store in dam water.

Question: 7

When does a force do work? Explain.

Answer: 7

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When force acts on the body and body covers some distance in the direction of force then we said force do work.

Question: 8

What is meant by efficiency of a system?

Answer: 8

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Efficiency of a system is the ratio of required form of energy obtained from a system as output to the total energy given to it as input. Formula: Efficiency = Required form of output/total input energy

Question: 9

Name the device that converts mechanical energy into electrical energy.

Answer: 9

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Generator is a device which converts mechanical energy into electrical energy.

Question: 10

Define unit of work.

Answer: 10

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Unit of work is joule. Amount of work is one joule when a force of one newton displaces a body through one meter in the direction of force. 1 J = 1 Nm

Question: 11

When does a foce do work

Answer: 11

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When foce acts on the body and body covers some distance in the direction of force then we said force do work

Question: 12

Define Elastic potential energy.

Answer: 12

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Elastic potential energy: The energy possessed due to stretched position in a body is called elastic potential energy. It is stored potential energy in compressed spring.

Question: 13

Define energy, give two types of mechanical energy.

Answer: 13

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A body possess energy if it is capable to do work. Unit: Its unit is joule Quantity: It is scalar quantity Types of mechanical energy: i. Kinetic energy ii. Potential energy

Question: 14

What are effects of fossil fuels on human health?

Answer: 14

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It causes serious health problem such as headache, tension, nausea, allergic reaction and irritation of eyes. nose and throat.

Question: 15

Give a example of the renewable energy source.

Answer: 15

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Sun light and water power are renewable energy source.

Question: 16

How solar energy can be converted directly into electricity?

Answer: 16

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Solar energy can be converted directly into electricity by solar cells.

Question: 17

What is photo cell?

Answer: 17

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A solar cell also called photo cell is made from silicon wafer. When sunlight falls on a solar cell. It converts the light directly into electrical energy.

Question: 18

Define mechanical energy.

Answer: 18

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Energy in required form obtained from a working system is always less than the energy give to it as input. Because every system meet energy losses due to friction in the form of heat, noise etc.

Question: 19

Write down the name of two nuclear reactions.

Answer: 19

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Fission and Fusion are two major reactions which give out nuclear energy.

Question: 20

Define potential energy also give its formula

Answer: 20

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Potential Energy: The energy possessed by a body to do work due to position is called potential energy There are two type of potential energy

Question: 21

Write the bigger units of power.

Answer: 21

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Bigger units of power are kilowatt , megawatt, horse power.

Question: 22

What is Magma?

Answer: 22

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In some parts of world,the Earth provided us hot water from geyser& hot spring there is hot molten part, deep in earth called magma.

Question: 23

Name the five devices that convert electrical energy into mechanical energy

Answer: 23

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The electrical energy is converted into mechanical energy by

Electrical motor

Drill machine

Electric fan

Grinder

Elevator

Question: 24

Give the uses of solar cells.

Answer: 24

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Solar cells are used in calculators, watches and toys.

Question: 25

What is meant by effieciency of a system

Answer: 25

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Efficiency of a system is the ration of required form of energy obtained from a system as output to the total energy given to it as input

Question: 26

What is meant by bio mass energy?

Answer: 26

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Biomass is plant or animal wastes that can be that can be burnt as fuel. Other forms of biomass are garbage, farm wastes, sugarcane and other plants. The energy obtained from biomass is called biomass energy.

Question: 27

Why fossil fuels are called non-renewable form of energy

Answer: 27

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The fossil fuels are one used to get energy that are consumed completely and these took millions of year for their formation So these are no renewable.

Question: 28

Why do we need energy

Answer: 28

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Energy: A body possesses energy if it is capable to do work

Question: 29

Why output energy is always less than the input energy

Answer: 29

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The energy in required form obtained from a working system is always less than the energy given to it us input Because every system meet energy losses due to friction in the form of heat noise etc

Question: 30

What are solar panels.

Answer: 30

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Large number of solar cells are wired together to form solar panels

Question: 31

State law of conservation of energy.

Answer: 31

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Energy can neither be created nor be destroyed but can be converted from one form in another . Example; When we rub our band our muscular energy converts into heat energy.

Question: 32

Define energy give two types of mechanical energy

Answer: 32

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Energy: A body possesses energy if it is carpetable to do work

Question: 33

Mechanical energy converts into heat energy tive its example.

Answer: 33

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Mechanical energy converts into heat energy. Example: Rub your hands together quickly . You will feel them warm. You have used your muscular energy in rubbing hands as a result heat is produced.

Question: 34

How is energy converted from one form to another

Answer: 34

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Energy can be converted from one from to another form For example heat energy is converted into mechanical energy and electrical energy can be converted into light energy

Question: 35

Which form of energy is most preferred and why

Answer: 35

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Solar energy is preferred to others.

Question: 36

Give example of the renewable energy source

Answer: 36

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Sun light and wither power are renewable energy sources

Question: 37

What are effects of fossil fuels on human health

Answer: 37

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It causes serious health problem such as headache, tension, nausea, allergic reaction and irritation of eyes, nose and throat.

Question: 38

Define Walt

Answer: 38

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Walt The SI unit of power is Walt One Watt is power of a device which does 1 j of work in 1 sec

Question: 39

How can you find the efficiency of system

Answer: 39

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Efficiency of a system is the ratio of required form of energy obtained from a system as output to the total energy given to it as input

We can find the efficiency of a system by following formula

Question: 40

What is photo cell

Answer: 40

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A solar cell also called photo cell is made from silicon wafer. When sunlight falls on a solar cell it converts the light directly into electrical energy.

Question: 41

Define mechanical energy

Answer: 41

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Mechanical Energy: Energy possessed by a body both due to its motion or position is called mechanical energy it has two types

Kinetic energy

Potential energy

Question: 42

Define unit of work

Answer: 42

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Unit of work is joule (J)

Amount of work is one joule when a force of one newton displace a body through one meter in the direction of force

Question: 43

State law of conservation of energy

Answer: 43

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Law of Conservation of Energy: Energy can neither be created nor be destroyed but can be converted from one form to another

Question: 44

A crate is moved by pulling, with mass the attached to it.

Answer: 44

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Given Date: F=100 N

S =10M

Question: 45

When does a force work

Answer: 45

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In physics, work is done when a force acts on a body and moves it in the direction of the force

Question: 46

Write down the name of two nuclear reactions

Answer: 46

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Fission and fusion are two major reactions which give out nuclear energy

Question: 47

What is meant by term power

Answer: 47

47-118

The rate of doing work is called power

Question: 48

Mechanical energy can be converted in heat energy

Answer: 48

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Explain with an example: By rubbing hands quickly these will be warmed Its means b rubbing hand muscular energy is used and as a result heat is produced, In this process of rubbing hands mechanical energy is converted into heat energy

Question: 49

How nuclear energy is obtained

Answer: 49

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Nuclear Energy: It is a form of energy which is released from the nucleus due to nuclear reactions such as fission or fusion reactions

Question: 50

What is magma

Answer: 50

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Magma In some parts of world, the Earth provided us hot water from geyser hot spring There is hot molten part deep in earth called magma.

Question: 51

What is meant by Geothermal energy

Answer: 51

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Geothermal energy: In some part of word the Earth provides us hot water from geysers and hot springs There is hot molten part deep in the Earth is called magma. Water reaching close to the magma changes to steam due to high temperature of megma This energy is called geothermal energy

Question: 52

Write names of two non-renewable and renewable sources of energy

Answer: 52

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Non renewable sources of energy are

Fossil fuels

Nuclear fuels

Renewable source of energy are

solar energy, Wind energy

Question: 53

On which parts solar house heating system consist of

Answer: 53

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A collector

A storage device

Distribution system

Question: 54

What is soil erosion

Answer: 54

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As the rain water flows down its kinetic energy changes into thermal energy while parts of the kinetic energy of following water is used to wash away soil particles of rocks known as soil erosion.

Question: 55

Define kinetic energy also give its formula

Answer: 55

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The energy possessed by a body due to its motion is called kinetic energy

Question: 56

Where and why catalytic converter is to be used

Answer: 56

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New cars have catalytic converters, These devices convert some polluting gases.

Question: 57

Prove that

Answer: 57

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P=W/t

P=f.s/t

P=F.v

Question: 58

What is meant by chemical energy

Answer: 58

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Chemical Energy: The energy released from substances during chemical reactions is called chemical energy

Question: 59

Give the use of solar cell

Answer: 59

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Solar cells are used in calculators watches and toys.

Question: 60

Give purposes of solar panels

Answer: 60

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Solar panels can provide power to telephone booths, light house, scientific research centres and satellites.

Question: 61

Define Potential energy and write its formula.

Answer: 61

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Potential Energy:

The energy possessed by a body due to its position is known as its potential energy P.E = mgh

Question: 62

Write the bigger units of power

Answer: 62

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Bigger Units bigger units of power: Bigger of power are kilowatt (kw), megawatt (MW) horse power The relation between them is as follow

Question: 63

What are solar panels

Answer: 63

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Large number of solar cells are wired together to form solar panels

Question: 64

Write the uses of wind energy

Answer: 64

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Use of Wind Energy: Wind energy is used as a source of energy for centuries

It has been used by windmills to grind grain and pump water It is also used to turn wind turbines.

Question: 65

Define kinetic energy and write tis equation

Answer: 65

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Kinetic energy: The energy possessed by a body due to its motion is called its kinetic energy

Education K.E=1/2

Question: 66

Define work and energy

Answer: 66

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Work: Work is said to be done when force acting on a body displaces it in the direction of the force.

Question: 67

Write names of two renewable energy sources

Answer: 67

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Name of renewable energy sources are

Energy from water, Energy from the sun, Biomass, Wind energy, Geothermal energy sources.

Question: 68

Define Energy

Answer: 68

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Energy Ability of a body to do work is called energy

Question: 69

Mechanical energy converts into heat energy give its example

Answer: 69

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Mechanical energy converts into heat energy

Example: Rub your hands together quickly You will feel them warm You have used r muscular energy in rubbing hands as a result heat is produced

Question: 70

On which factor work depends

Answer: 70

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Work: Work is done when a force acting on a body displaces in the direction of force

Formula: it is a scalar quantity

Question: 71

Define elastic potential energy

Answer: 71

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The energy possessed due to stretched position in a body is called elastic potential energy. It is stored potential energy in compressed spring

Question: 72

Name two devices that convert electrical energy into mechanical energy

Answer: 72

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D.C motor and Electrical fane are those devices which convert electrical energy into mechanical energy

Question: 73

Differentiate between electrical energy and light

Answer: 73

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Electrical Energy: Electricity is one of the widely used form of energy

Electrical energy can be supplied through wires easily to any desired place

Electrical energy can get from batteries and electric generators.

Question: 74

What is meant by bio mass energy

Answer: 74

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Bio Mass: Biomass is plant or animal wastes that can be burnt as fuel Other forms of biomass are garbage, farm wastes, sugarcane and other plants. The energy obtained from biomass is called biomass energy

Question: 75

How Biomass is used to obtain energy

Answer: 75

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There are different ways to get energy from biomass Some of these are as follow

Different forms of biomass are used to run power plants.

Many Industries that use forest products get half of their electricity by burning Burk and other wood wastes electricity by burning Burk and other wood wastes

Plants and animal wastes can be burnt as fuel

Question: 76

What are the major sources of energy?

Answer: 76

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Major sources of energy are as following .

1-Fossil fuels

2-Nuclear Fuels.

Question: 77

How do we gain energy from air

Answer: 77

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Wind has power sailing ships across the oceans It has been used by windmills to grind grain and puop water Now wind power is used to turn wind turbines. When many wind machines are grouped together on wind forms they generate enough power to operator a power plant

Question: 78

Define heat energy

Answer: 78

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Heat Energy: A form of energy given out by hot bodies is called heat energy

Question: 79

Write equation for K.E and P.E

Answer: 79

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Kinetic energy: K.E 1/2

Where m is mass and v is velocity of body

Question: 80

Differentiate between solar cell and solar penal

Answer: 80

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Solar Cell: Solar cell is made up from silicon water

Solar cells are used in calculators watches and toys.

Question: 81

Write brief note on Einstein mass energy equation

Answer: 81

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Einstein predicted the interconversion of matter and energy. According to him, a loss in the mass of a body provides a lot of energy This happen in the nuclear reaction The reaction between the mass m and energy E is given by Einstein's mass energy equation

The above equation shows that tremendous amount of energy can be obtained from small quantity of matter It happens that matter is a highly concentrated form of energy

Question: 82

Differcreate between Mechanical energy and Sound energy

Answer: 82

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Mechanical Energy: energy possessed by a body due to its motion or change in position is called mechanical energy

Question: 83

Define chemical energy and write one method to obtain it

Answer: 83

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Chemical Energy: Energy produce during chemical reactions is called chemical energyMethod to Obtain it: Burning of coal, natural gas and wood in arit is chemical reaction which release energy as heat and light.

Question: 84

Define efficiency and write its equation

Answer: 84

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Efficiency: Efficiency of a system is the ratio of required form of energy obtained from a system as output to the total energy give to it as input

Question: 85

Define mechanical energy and write its types

Answer: 85

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Mechanical energy: The energy possessed by a body both due to its motion or position is called mechanical energy

Question: 86

How solar energy can be converted directly into electricity

Answer: 86

86-118

Solar energy can be converted directly into electricity by solar cells

Question: 87

Define potential energy and write its formula

Answer: 87

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Potential energy: The energy possessed by a bogy due to tis position is known as its potential energy

Question: 88

Write down two ases of thermal pollution.

Answer: 88

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Global warming is the major causes of thermal pollution. The heat produced bby fission reaction causes thermal polution.

Question: 89

How a pole vaulter acquired changes of energy?

Answer: 89

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Pole culture is capableto store all the vaulter's Kinetic energy while bending in the form of potential energy.

Question: 90

How is energy produced from nuclear fuels

Answer: 90

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The energy is produces from nuclear fuels by nuclear reactions such as fission and fusion reactions.

Question: 91

Define power and watt

Answer: 91

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Power: The rate of doing work

Question: 92

Define fission reaction

Answer: 92

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Fission reaction: Nuclear fussion is the process in which a large nucleus splits into smaller nuclei with the release of energy

Question: 93

What is difference between kinetic Energy and potential Energy

Answer: 93

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Kinetic Energy: The energy possessed by a body due to its motion is called its kinetic energy.

Kinetic energy is represented by k.e

Question: 94

Write down the two disadvantages of fossil fuels

Answer: 94

94-118

Fossil fuels release harmful waste products. These wastes include carbon mono-oxide and other harmful gases which pollute the environment

Long espouse of these harmful gases may cause as the mas, lungs, cancer, heart diseases and even damage to bran, nerves and other organs of our body.

This causes serious health problems such as headache, Tension, nausea, allergic reactions, irritation of eyes, nose and throat.

Question: 95

On what parts a heating system consist of

Answer: 95

95-118

A heating system consists of the following factors

A collector, A storage device, A distribution system

Question: 96

Define kinetic EnergyWrite its equation

Answer: 96

96-118

Kinetic Energy:

The energy possessed by a body due to its motion is called its kinetic energy.

K.E =1/2 mv²

Question: 97

To construct such a working system whose efficiency is 100% is impossible Why

Answer: 97

97-118

To construct such a working system, whose efficiency is 100% is impossible because every system meets energy losses due to friction that causes heat, noise etc These are not the useful form of energyh and go waste.

Question: 98

What is meant by Energy from Biomass

Answer: 98

98-118

Biomass is plant or animal wastes also when animal during dead plants and dead animal decompose, they give off a mixture of methane and carbon dioxide. Electricity can produce by burning methane.

Question: 99

Define Work and Joule

Answer: 99

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Work: Work is done when a force acting on a acting on a body displace it in the direction of a force

Question: 100

Write the names of major sources of Energy

Answer: 100

100-118

Major Source of Energy

Fossil fuels, Nuclear fuels, Sun, Water

Question: 101

Define work. Write formula and unit.

Answer: 101

101-118

Work:

Work is done when a force acting on a body displaces it in the direction of a force

Work done = force x displacement

W= FS

Question: 102

What is meant by Nuclear Energy

Answer: 102

102-118

Nuclear Energy: Energy released in various nuclear reactions like fission and fusion reaction is called nuclear energy

Question: 103

A body of mass 50 kg is raised to a height of 3m what is its potential energy?

Answer: 103

103-118

m= 50kg

h = 3m

P.E = Mgh

= 3 x10 x 50

P.E = 1500

Question: 104

Write the mass energy equation and value of speed of light

Answer: 104

104-118

Mass Energy Equation: The Einstein's mass-energy equation states that mass and energy are interconvertible to each other

Question: 105

How much work is done when a body moves with uniform velocity?

Answer: 105

105-118

When a body moves with uniform velocity means moving with zero acceleration then work done will be zero

Question: 106

Differentiate between mechanical and chemical energy

Answer: 106

106-118

Mechanical Energy: The energy possessed by a body both due to its motion or position is called mechanical energy moving car wind lifted hammar posses mechanical energy

Question: 107

Why fossil fuels are called non- renewable source of energy?

Answer: 107

107-118

Fossil fuels are called non renewable source of energy because they will run out like coal, oil and gas.

Question: 108

Name such a device that converts mechanical energy into electrical energy

Answer: 108

108-118

Generator is a device that converts mechanical energy into electrical energy

Question: 109

How much power is used by a 40Kg athleteby climbing 10m high ladder in 10s

Answer: 109

109-118

m = 40 kg

t = 10s

h=S = 10m

F= w

F= mg

F= 4 x 10

F= 400N

Question: 110

Define geothermal energy and elastic potential energy

Answer: 110

110-118

Geothermal Energy: There is hot molton part, deep in the earth called magma water reaching close to the magma charges to steam due to the high temperature of magma This energy is called geothermal energy This energy can be utilized by drilling deep in the earth

Question: 111

A cyclist does 12 joules of useful work while pedaling his bike from every 100 joules of food energy which he takes. What is his efficiency?

Answer: 111

111-118

W= 12J

E= 100 J

Efficiency = 12J/100J

= 0.12

% Efficiency = 0.12 x100

= 12%

Question: 112

Write two uses of wind energy

Answer: 112

112-118

Uses of wind energy

Wind energy has powered sailing ships across the oceans

Wind energy has been used by windmills to rind grain and pump water

Question: 113

What is the second name of solar cell and how it made

Answer: 113

113-118

A solar cell also called photo cell. Solar cell made from silicon wafer. When sunlight falls on a solar cell, it converts the ight directly into electrical energy Solar cells are soused calculators, watches and toys.

Question: 114

What two sources of non-renewable energy

Answer: 114

114-118

Non-renewable: Those sources of energy which finish with continous use of these source are called source of non-renewable energy

Fossil fuels,Nuclear fuels

Question: 115

Write uses of energy, pollute our environment?

Answer: 115

115-118

Burning of fuel and solid wastes in homes, automobiles and factories release harmful amounts of air pollutants

2- Nuclear power plants do not produce carbon dioxide, but they produce dangerous radioactive waste

Question: 116

Define Elastic potential energy and give its example.

Answer: 116

116-118

Elastic Potential Energy:

The energy present in the stretchedbow is called elastic potential energy. A stretchedbow has potential energy due to its stretched position

Question: 117

Write two disadvantages of thermal pollution

Answer: 117

117-118

Thermal pollution upsets the balance of lift

Thermal pollution endanger the survival of many species.

Question: 118

Name the five devices that convert electrical energy into mechanical energy.

Answer: 118

118-118

1- Electric Motor

2- Electric Fan

3- Elevator

4- Drill machine

5- Grinder Sewing machine

Physics Chapters

9th Class Chapter 6 Physics Short Questions

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