Download 10th physics notes - Uday Pre

Types of Motion
Std
X
Choose the correct answer

Which of the following represent the circular motion---------(
 Ball sliding down an inclined plane
pendulum
b.
d)
motion of simple of
 A freely falling body
to a thread and whirled
d.
A stone tied
 The waves carries --------------( b )
 Power
d.
work
b.
energy
c.
displacement
 Which of the following is longitudinal wave---------------( d )

Radio wave
d. sound waves
b.
X- rays
c.
light wave
 The S.I unit of wave length is -----------------( c )

Cm
b.
d.
dm
c.
m
km
 The wavelength of a wave is 4 m and two wave per second possess a
point , Then the speed of the wave is -----------------
Q II
2 m/s
6m/s
b.
d.
8 m/s
4 m/s
Complete the following sentences
 Waves are produced by
distrubances .
 The speed of a wave depends on
nature of the medium
c.
 The distance between two consecutive compressions
wave length .
/ rarefaction
 The type of wave to which electromagnetic wave belongs to
transverse wave .
 In a longitudinal wave the vibration of particles
wave are
same
Q
III
, and the direction of
Match the following
A
B
 Longitudinal wave
Oscillations in spring
 Transverse wave
Crests and tough

Simple harmonic motion
simple pendulum
Q
IV
Oscillation of a
Answer the following
 Give differences between a transverse wave and a longitudinal wave
Transverse wave
Longitudinal wave
The wave propogates in the
propogates in the form of crests and toughs
form of compressions and
The wave
Rarefaction
 One crests and one trough
compression and one
one
Constitute a wave
rarefaction constitute a wave
Q 2. Does the particles of the medium in which a wave moves travel along
with the wave? Explain with an example.
Ans The particles of the medium in which a wave moves, do not travel
along with the wave. This can be shown by the following activity. Place a paper
ball on the surface of water in the pond. Throw a small pebble to the still water.
You will find the waves forming and these waves are transverse waves observe
the paper ball it is moving up and down only , but it is not moving forward along
with the waves . Only energy is carried.
 If we double the frequency of a vibrating object, what happens to its time
period ?
Ans. Time period and frequency are inversely proportional to each other. If we
double the frequency of a vibrating object, then the time period of vibration
reduces to half.
4 If the frequency of tranverse wave is 10hz and the distance between the two
consecutive wave crests is 2m. Calculate the wave speed.
A.If the frequency of a wave motion is f and the distance between the two
consecutive wave crests λ, then the speed of the wave is denoted as ‘v’
V=fλ
given
f = 10Hz
λ = 2m
v = 10 X 2 = 20m/s
5 define simple harmonic motion and give two example of the same .
A A particle is said to be in simple harmonic motion if the acceleration of the
particle is always directed towards a fixed point called mean position and the
magnitude of the acceleration is directly proportional to the displacement of
the particle from mean position.
Eg – i) Oscillation of a simple pendulum.
ii) When a tuning fork is hit against rubber pad, its prongs execute
Simple
Harmonic Motion.
6 Give two practical applications of Simple Harmonic Motion.
A 1. Simple Harmonic Motion of a pendulum used for calculating time in clocks
2. Tuning the musical instrument is done with the vibrating tuning fork
which executes simple harmonic motion.
Std
VII
Q
Cellular Organization
I
Choose the correct answer
 Microscope was invented by
Leeuwenhoek.
 Leeuwenhoek
c.
Robert Hook
Robert Brown
b.
d.
 Cell was discovered by
Robert Hook
 Leeuwenhoek
Robert Hook
Brown
b.
b.
 The power house of a cell is
Q
II
b.
bacteria cell
tissue
d.
Robert
c. virus
mitochondrion
ribosome
d. lysosome
c.
A group of cells with similar structure and function is
a.
system
c.
eukaryotic cell
 Prokaryotic cell
d. eukaryotic cell
5.
Parashara
d.
 A true nucleus is present in
a..Nucleus
mitochondrion
Parashara
b.
organ
a
tissue
c.
organ
organism
Fill in the blanks
 The combination of different
system
organs which out a particular function is a
 Ribosome helps in protein synthesis.
 Lysosome helps in the digestion of
organic substance.
 Paramecium
is an example for unicellular organism
 The part which controls and co-ordinate
nucleus
all the activities of the cell is
 In a prokaryote , genetic material is represented by chromatin
Q III
Answer the following
 Define a cell. Explain the structure of a typical cell
Ans. A cell is the structural and functional unit of an organism. The cell has a
and organelles like mitochondria , endoplasmic reticulum , and golgi complex.
 Draw a neat diagram of
Ans
eukaryotic cell and
Refer page No . 18
 Difference
label its parts.
fig. 2.2
between an organ and a tissue
Organ It is a combination of different types of tissues which performs
specific function.
Tissue A tissue is a group of cells with similar structure and function.
 Mention the
Ans
Nucleus
functions of the
parts of a eukaryotic cell.
Controls and co-ordinates all the activities of the cell.
Mitochondrion
Helps in producing energy from food .
Ribosome
Helps in protein synthesis.
Centriole
Helps in cell division .
Vacuole
Stores wastes , secretions and reserve food products in the
cell.
Endoplasmic reticulum It transports substances
cell to the other and from one cell to another.
from one part of the
a
Golgi complex
activities .
It helps in the secretion of chemicals
required for cellular
Lysosome
Helps in the digestion of organic substances present in the cell.
It destroys its own cell when cell become old or damaged.
 Distinguish between the following pairs
Ans
Prokaryotic cells
Eukaryotic cells
 The cytoplasm shows
The cytoplasm shows
small ribosome
large ribosome.

Genetic material is
Genetic material is present in the represented by
form of chromatin.
DNA
b)
Unicellular organisms
Multicellular organisms
Organisms with a singke cell are
many cells are
organisms with
called unicellular organisms .
organisms.
Eg. Banyan tree, elephant
Amoeba, euglena etc
multicellular
etc.
 Draw a neat labelled diagram
eg.
of a prokaryotic cell.
Ans
Refer page No 17
Fig .
2.1
 Describe the structure of a prokaryotic cell.
Ans
The cell is surround by cell membrane and a cell wall. The genetic
material is represented by nacked Deoxy Ribo Nucleic Acid. The cytoplasm
shows small ribosome. A cell with this pattern of organization is called a
prokaryotic cell.
 Name the four levels of our body organization in organisms
Ans
The four levels of our body organization in organisms are Cell.
Organ, and System .
Tissue ,
 n the advantage of tissue-organ level of body organization.
Ans . The advantages of tissue – organ level of body organization is that cell
differentiate into true tissues and organs for specific functions.
Std
X
Q
I
Physics
Stars and Galaxies
Choose the correct answer

The raw material for the formation of protostar is

In which of the following stage is the Sun
Red giant,
white dwarf,
protostar,
hydrogen.
steady state
steady state

The first element formed within few minutes after supernova is

The heaviest element formed in the stellar evolution before supernova explosion is iron
oxygen.

The diameter of Milky Way is about one lakh light year
Q II
Match the following
A
B

The Sun
Yellow

The Sirius
Yellowish white

The Rigel
Bluish white
Q
III

Answer the following
How is a protostar formed ?
Ans.
The inner stellar space contain huge gaseous clouds of hydrogen. This huge cloud
continuously contracts under its own force if gravity with increase in density. This leads to increase
in pressure with maximum density at the centre. This central portion ,which constitute about 99% of
the mass of gaseous cloud is refered as protostar.

When does a star attain Steady state?
Ans. The continuous contraction of the gaseous cloud of the protostar leads to an increase in the
temperature so much so that hydrogen molecules begin to fuse to form helium. This nuclear reaction
releases tremendous amount of energy , which tries to push the matter away the from the centre.
However the force of gravity eventually balances the pressure caused by the radiation from the
nuclear reaction and the star reaches the steady state.

Explain the evolution of a star whose mass is five times the mass of a star
Ans.
Stars which are five times the mass of the sun evolve differently after red giant stage.
Their evolution has several stages of nuclear reactions ignited one after other . The carbon nuclei
produced during the fusion of helium ,forms the carbon core . The carbon nuclei fuse and liberate
energy synthesizing heavier element like oxygen, magnesium and silicon. This fusion cycle repeats
until the element iron is formed . At this stage the star explodes in the form of supernova. The
remnant condenses in the form of neutrons to form neutron star.

Explain the Big Bang theory.
Ans. It is proposed that the universe might have begun with a start of explosion known as big
bang . Everything what we have in the universe was once concentrated in a very small hot
place called ‘’Primordial Fire Ball’’ something triggered and the fire ball exploded with a bang
and the matter in it was thrown away. This is known as big bang theory.

State Hubbles’s law
Ans.
The velocity of recession of a celestial body is proportional to its di stance from us
( B)
Q
I
Rockets and Artificial Satellites
Answer the following

Explain the principal of rockets
Ans.
Working of a rocket is based on the following principle

Newton’s third law of motion

The principle of conservation of momentum.
According to Newton’s third law of motion “ For every action there will be an equal and opposite
reaction”
According to principle of conservation of momentum “The total momentum of a system is
conserved when the net force acting on the system is zero”
Let a bullet of mass ‘m’ is fired with a velocity ‘v’ from a rifle of mass ‘M’ Before firing both the
bullet and rifle are at rest which means the total momentum is zero
When the bullet is fired ,the bullet leaves the nozzle of the rifle with a momentum ‘mv’ and the rifle
recoils with a velocity ‘V’ There momentum of the rifle is ‘MV’
Total momentum after firing is
mv +MV
The total momentum must be zero.
MV+mv=0
or
MV
mv
The rocket works in the same principle
During the firing of a rocket the fuel burns and is converted into gas at high pressure. The gas escape
from NOZZLE of the rocket with a high velocity and rocket is pushed with a high velocity in the
opposite direction.
2
Ans.
Page no 403
3
Ans.
Draw a neat diagram of single stage rocket and label the parts.
fig 24.13
Define orbital velocity of a satellite
The velocity of the satellite along a circular path is called orbital velocity.
4
and orbital velocity
What is meant by escape velocity? Write the relation between escape velocity
Ans. The maximum velocity with which a body must be projected so that it escapes from the
gravitational field of earth is called escape velocity (V e )
Relation between Orbital velocity and escape velocity
Orbital velocity V 0 =
Escape velocity V e =
:.
Ve
5
=
V0
What are the factors that decide the value of escape velocity
Ans. Escape velocity depend upon the radius of the earth (R) and acceleration due to gravity (g)
6
Ans .
What are multistage rockets? What are their advantages .
Multistage rockets are several rockets joined together one on top of the other to provide
Advantages of multistage rockets 1) The fuel consumption can be reduced 2) Increases
the efficiency of the rocket 3) At a greater height satellites can be placed.
7
Make a list of artificial satellites.
Ans.
following are the main uses of artificial satellites.

Communications

Agriculture.

Weather forecasting

Flood forecasting

Identifying Geological mineral resources

Identifying underground water sources

Monitoring air, water, sound and thermal pollution

Forest fire detection

Detecting ‘’Elmino’ type weather changes etc
8
Write an essay on Indian space programme
Ans.
Indian space programme was started in 1963 with launching of a research
rocket from Thumba . In 1969 Indian space Research Organization ( ISRO) was established. In the past
five decades ,India has many achievements to its credit in space. ISRO had built and successfully
launched various types of satellites .They include communication satellites ,and scientific satellites
These satellites are providing many valuable services to India like telephone calls, internet data rely,
accurate weather forecasting , accurate survey of the country’s resources, etc ISRO constructed many
satellites such as Polar Satellite Launch Vehicles( PSLV), Geosynchronous Satellite Launch Vehicles(
GSLV), INSAT series of satellites were also constructed. PSLV launched many foreign satellites in addition
to the Indian ones.
India took a giant leap towards the moon In 2008 ISRO sent “”Chandrayaan—1
an unmanned spacecraft to explore the moon. This Chandrayana mission succeeded in finding water on
the surface of the moon. This is the greatest achievement in space by India. In November 5th 2013 ISRO
launched a spacecraft to explore planet Mars. This spacecraft was sent using cryogenic engine fitted
rocket. Construction of cryogenic engine is the most modern technology. India can hope to have
manned mission to moon in future.
Sound
I
Choose the correct answer
i
Echo of sound is due to reflection of sound.
ii
The property of ultrasonic waves used in manufacturing emulsion for
photographic films is its higher wavelength.
iii
When a source emits light of particular wavelength and the source is moving
away from us, the wavelength appears longer.
iv
The audible range in human is 20 Hz to 20000 Hz.
v
The speed of ultrasonic sound in air is 340ms -1
II
Fill in the blanks
i
The sound wave is of the type longitudinal wave.
ii
Ultrasonic is preferred to X ray in medical field because it is less harmful.
iii
When ultrasound is used to examine heart, it is called Echo cardiography
iv
The shift caused in visible spectrum of light emitted by galaxies is red
shift.
III
Match the following
A
B
IV
1
Radar
a) electromagnetic
2
Sonar
b) ultrasound
3
Doppler Effect
c) apparent shift in frequency
Answer the following
 What is an echo? Mention the condition for echo to be heard.
A The sound heard after reflection from a rigid surface is called echo.
The conditions for the echo to be heard
i To hear a distinct echo the time interval between the original sound
and the reflected sound must be equal to 0.1s.
ii The reflecting surface should be at a minimum distance of 17m from the
listener.
 An ultrasonic sound sent from a ship travels with the speed 1530 ms -1 in sea
water. How deep is the water if the time delay of the echo from the sea bed
is 6s ?
A
Speed ‘v’ of the sound in sea water = 1530 ms -1
Time taken by the sound to reach the ship = 6s = t
The depth of the sea water = ‘d’
Then
d=
= = 1530 X 3
= 4590 m
Depth of sea water = 4590m
 What is SONAR? How does it work?
A
Sonar is the acronym of “Sound Navigation and Ranging“. This is a
technique by which ultra-sonic waves are used to measure the distance,
direction and speed of under water objects.
Working of Sonar
A sonar contains a transmitter and a receiver (detector).
The transmitter produces and transmits ultrasonic waves. These waves
travels through water until they strike an object. They get reflected and the
reflected and the reflected waves return to the detector of the sonar. The
detector converts the received ultrasonic waves into electrical signals which
are interpreted. The time interval between transmission and reception is
recorded. The distance of the object is calculated.
 What is Doppler’s effect ? explain with an example.
A When either the source of the wave of sound/light or an observer is moving
relative to each other, then there is an apparent change in the frequency of
the wave. This is known as the Doppler Effect.
When the source of the sound/light is moving towards the observer
the waves on front appear to be compressed. The observer feels sound to be
of higher frequency. Therefore he feels the pitch of the sound to be higher.
The same effect is observed when the observer is moving towards a
stationary source of sound.
 Mention three applications of Doppler’s effect.
A 1 Doppler effect can be used to track artificial satellite.
2 Doppler effect of sound can be used to determine the velocity of
submarines.
3 astronomers use Doppler effect to gauge the movement of stars and
galaxies with relative earth.
***************************************
Electromagnetic Induction
I
Fill in the blanks
 Device that converts mechanical energy into electrical energy is dynamo.
 The type of electric current that changes its direction twice during one
cycle of the dynamo is called alternating current.
 Device that converts electrical energy into mechanical energy is motor.
 In Fleming’s rule the middle finger indicates the direction of induced
current.
 The device that detects the induced emf is called galvanometer.
II
Choose the correct answer
 Electricity and magnetism are mutually ___complementary.
 The SI unit of potential difference is ____volt.
 Carbon brushes are not necessary in a dynamo, if the coil remains
stationary and the magnet moves because___-current is drawn from a
stationary source.
 AC is not suitable for electrolysis because----polarity of the current
changes.
 Which of the following graph indicates direct current------d.
 When the plane of the rectangular coil is parallel to the to the direction of
the magnetic field in a dynamo, then--- induced current will be zero.
 A small AC dynamo is connected to a galvanometer and gently rotated
,then the needle of the galvanometer -----moves towards both right and
left.
 A dynamo makes 100 cycles per second. The frequency of the AC is 100
Hz
III
Answer the following
 What is electromagnetic induction ?
When the magnetic field linked with a circuit changes an emf will be
induced in the current. This phenomenon is called electromagnetic
induction.
 State Faraday’s laws of electromagnetic induction.
I Law---Whenever a magnetic field linked with a conductor changes an
induced e.m.f is generated in the conductor.
II law---The magnitude of induced emf is directly proportional to the rate
of change of magnetic field linked with the conductor.
 State Fleming’s right hand rule . For what purpose it is used ?
Fleming’s right hand rule----Arrange the first three fingers of right hand
mutually perpendicular to each other. The fore finger indicates the
direction of the magnetic field, the thumb the direction of the conductor,
then the middle finger will indicates the direction of the induced emf.
This rule is used in the working of dynamo.
 Draw neat diagram of the following and label the parts i)

Ans
AC dynamo
ii) DC dynamo iii) DC motor
i) AC dynamo refer page no 264 fig 16.5
ii) DC dynamo refer page no 266 fig 16.7
iii)DC motor refer page no 267 fig 16.10
 Mention any two uses of DC and any two uses of AC
Uses of DC current


Battery charging ( adoptor ) electrolysis
Charging of mobile phones
Uses of AC current

In domestic appliances like lamps , fans

To produce required frequency of radio waves.
Q V
Give reason
 In the experiment conducted by Faraday the induced electricity
current was not DC.
 Magnet pushed into the coil gives one direction of the current and
removal of the magnet gives the opposite direction of the current
which is AC not DC.
 Split rings are used instead of slip rings to construct DC dynamos.
 The split rings reversed the connection to the external circuit. This
makes the current to flow in the same direction. Therefore split rings
are used to construct DC dynamo.
 Stationary coil and stationary magnet cannot produce induced electric
current.
 An emf will be induced in the circuit only when the magnetic field
associated with a close circuit changes. So stationary coil or
stationary magnet cannot produce clear current.
VII Draw neat diagram of the following and label the parts
 Step down transformer ----- refer fig 16.12 a
 Step up transformer --------- refer fig 16.12 b
 Induction coil ---------------
refer fig 16.12 c
Heat Engine
I
1 The energy transformation in a heat engine is
a mechanical into heat

b heat into mechanical
c mechanical into potential
d mechanical into chemical
2 forward movement of a piston in steam engine is called

a expansion stroke
b exhaust stroke
c intake stroke
d ignition stroke
3 In a steam engine the steam cylinder is connected to the condenser by
a piston
b crankshaft

c outlet valve
d inlet valve
4
both the valves of a petrol engine are closed during
a intake stroke
b exhaust stroke

c compression stroke
d fuel in the stroke
5 An engine is designed to convert 20% of the heat energy into work. If the steam in the engine
has 50kj of heat energy , the useful work done by the engine is

a 16kj
b 100kj
c 40kj
d 50kj
6 In a temporary forest camp, the best way to generate electricity for several hours is to use the
following engine
a steam engine
b petrol engine
c hand operated dynamo

d diesel engine
II Fill in the blanks
1 the part of petrol engine in which petrol vapour and air are mixed is carburettor.
2 Linear movement of the piston in a heat engine is converted into circular motion by crank
shaft.
3 The stroke of a heat engine in which outlet valve opens is exhaust stroke.
4 internal combustion engine that does not use spark plug is diesel engine.
5 The fuel used in Raichur thermal power plant is coal.
III Answer the following
1 An engine is 40% efficient. What is the meaning of this statement?
A 40% of the heat energy is converted into mechanical energy.
2 Make a list of the differences between petrol engine and diesel engine
Diesel engine
i diesel engine are compression
ignition engines.
Petrol engine
i petrol engine are spark ignition
engines.
ii spark plug is not required
ii spark plug is required
iii micells of diesel are as fuel.
iii petrol vapour is used as fuel
iv the cost of diesel is
comparatively less.
v expansion against constant
pressure.
vi efficiency is comparatively
more.
iv the cost of petrol is
comparatively high.
v expansion of gaseous products
with pressure impulse
vi efficiency is comparatively
less.
3 Make a list of the limitations of a steam engine.
A i Construction of steam engine is not simple. The bulk and the heavy weight
of the engine is not suitable for small vehicles.
ii The efficiency of the engine is very low.
iii Heating water to produce steam, takes time and the engine cannot start
instantly.
4 Explain the intake stroke of a petrol engine.
A In a petrol engine the vapourised mixture of petrol and air is let in through
the inlet valve. The outlet valve remains closed. Piston moves away from the
spark plug.
5 diesel engines do not require spark plug. Why ?
A In the place of spark plug there will be compressor in which reverse intake
and compression takes place. Due to high pressure of air diesel burns.
6 Draw a neat diagram of expansion stroke of a steam engine.
Ans
Refer page no.
113 figure 9.3 (a)
7 Draw a neat diagram of petrol engine and label the parts.
Ans
Refer No 115 figure 9.5
8 An engine is designed to convert 10kj of heat energy into work. If the heat
energy consumed by the engine is 60kj. How high would this engine lift an
object of mass one kilogram from the ground ?
A
Assume that g = 10m/s2
W = mgh
Efficiency =
E=
or
E = 40%
W=
H \ 60kj m = 1kg (1000g)
g = 10m/sec2
h = the height to be found
W=
=
= 24kj
W = mgh = h = = = 2.4m
Electronics
 The conductivity of a semiconductor is
 Greater than the conductivity of metals
 Less than the conductivity of metals
 Equal to the conductivity of metals
 Intermediate between the conductivity of metals and insulators
Answer --- d
 The conductivity of a semiconductor can be increased by
 Heating the semiconductor
 Doping the semiconductor
 Both a and b
 None
Answer ---- c
 In a n-type semiconductor which of the following statement is true ?
 Electrons are majority carriers and trivalent impurity are the dopants
 Electrons are minority carrier and pentavalent atoms are dopants
 Holes are minority carriers and pentavalent atoms are dopants
 Holes are majority carriers and trivalent atoms are the dopants
Answer ----- b
 Which of the statements given in question 3 is true for p-type
semiconductor?
 D
 When a forward bias is applied to p-n junction it
 Raises the potential barrier
 Reduces the majority carrier current to zero
 Lowers the potential barrier
 None of the above
Answer ----- c
 For transistor action which of the following statements is correct ?
 Base,emitter and collector regions should have similar size and doping
concentration
 The base region must be very thin and lightly doped
 The emitter junction is forward biased and collector junction is reverse
biased
 Both emitter junction and collector junction are forward biased
Answer ---- c
II Fill in the blanks
 In p-n-p transistor the majority carriers are holes.
 In n-p-n transistor the majority carriers are electrons.
 During reverse bias of the diode there is a small current of the order of
micro ampere due to minority charge carriers.
 In an n-p-n transistor p type semi conductor sandwiched between two n
type semi conductor.
 Pentavalent impurity is called n type impurity.
 Trivalent impurity is called p-type impurity.
 The traces of impurity added for doping are called dopants.
III
 What is electronics ?
 Electronics is an extended field of physics and engineering both pure and
applied.
 What are conductors and insulators. Give examples.

Conductors
Materials which conduct electric
current smoothly eg. All metals
Insulators
Materials which do not conduct
electric current smoothly. They
are also called non conductors or
bad conductors.
Eg; all non metals except graphite
 Mention any four electronic gadgets.
 C.D players, computers, mobiles, phones, amplifiers etc.
 Which are the areas influenced by electronics?
 The areas influenced by electronics are Industrial field, military
requirements fiels, communication field and medical science field.
 What are most recent advancements in the field of electronics ?
 The areas influenced by electronics are digital circuits, micro processor,
digital computers, photo electronics laser technology, nano technology
and so on.
 What are semiconductors?give examples.
 The substances which have conductivity in between conductors and
insulators are called semi conductors.
Ex : silicon, Germanium
 How many electrons are there in the outermost shell of silicon atom ?
 There are four electrons in the outermost shell of silicon atom.
 What is called a hole ?
 When an electron from a neighbouring atom moves a vacancy is created.
This vacancy is called hole. This is a positive charge carrier.
 Distinguish between extrinsic and intrinsic semiconductors.

Intrinsic Semiconductors
Extrinsic Conductor
i semiconductor are the crystalsi when some impurity atoms are
of pure elements like silicon added to this intrinsic semiconand germanium.-doctor we get extrinsic semicoii the number of electrons is equal -ndoctor.
to number of holes ne = nn ii the number of electrons is not
equal to the number of holes.
ne≠nn

Explain the term doping
 When a few atoms of trivalent or pentavalent element is added into
intrinsic semiconductor ( Germanium or silicon ) it converts to extrinsic
semiconductor. The process of adding impurity atom is also called
doping.


Distinguish between n-type and p-type semiconductors.
n-type semiconductor
semiconductors
p-type
i when pentavalent impurityi when trivalent impurity atoms
atoms like phosphorous, arseniclike gallium, indium, aluminium
or antimony are added to the intretc are added to the intrinsic semi
insic semi-conductor,we get n-type
conductor.
semi conductor.
ii the majority carriers in n-type
ii the majority carriers in p-type
semiconductor are electrons and
semi conductor are holes and
minority carriers are holes due to
minority carriers are electrons.
thermal energy.
 Name two pentavalent impurities.
A.Pentavalent impurities are antimony,arsenic and phosphorous

Name two trivalent impurities.
 Gallium, indium , Boron and aluminium ( any two )


What is semiconductor diode or junction diode.
A single crystal of semiconducting material whose one side is doped
with donor impurity and the other side is doped with acceptor impurity
forms a p-n junction diode or semiconductor diode.

What is meant by forward bias and reverse bias of a diode ? Indicate in a
figure.
 Forward bias of a diode : when the positive terminal of the battery is
connected to p-region and the negative terminal of the battery is
connected to n-region of the junction diode it is said to be forward biased.
For fig refer page no 281 fig 17.7
Reverse Bias of a diode : When the positive terminal of the battery is
connected to n-region and negative terminal of the battery is connected to
p-region of the junction diode it is said to reversed biased. For fig refer
page no 281 fig 17.8

Give the circuit symbol of a diode.
Ans For fig refer page no 282 fig 17.10


Mention important characteristics and applicatons of a diode.
The important characteristics of diode is it allows electricity to flow in
one direction and blocks the flow in the opposite direction.
Applications – diodes are used in voltage regulation systems. They are
used in logic circuits which are used in computers.


What is a transistor ?distinguish between p-n-p and n-p-n transistor.
A transistor is a three terminal semiconductor device. It is a resistor to
amplify electrical signal passing through its input to output terminals.
p-n-p transistor
two segments of p-type
semi
n-p-n transistor
two segments of n-type
semiconductor are separated by
a segment of n type semiconductor


conductor are separated by a
segment of p-type.
What are the functions of three regions of a transistor ?
A transistor consists of three regions. They are emitter (E), base (B) and
collector (C)
Functions of E,B and C of transistor.
Emitter : it supplies a large number of majority carriers for the flow of
current through the transistor.
Base
: it regulates the flow of charges from emitter to collector.
Collector : this segment collects a major portion of majority carriers
supplied by the emitter.

Mention the applications of a transistor.
 Transistors are used in

Amplifiers

Oscillators

Switching circuits.
Alternative
Q

I
Sources of Energy
Choose the correct answer
Identify from the following , a conventional source of energy---- ---(c)

Solar energy
d. bio energy
2.
3.
natural gas
b.
Kanyakumari
c.
Gujarath
d.
soil quality
b.
it enhances water
it reduces carbon dioxide content in the atmosphere
d.
it increases pollution
One of the following is an indirect form of energy--------( d )
a.
tidal energy
energy
d.
Q
c.
Which of the following is not a feature of bio energy-------( d )
a. it improves
retention
4.
tidal energy
The largest installation of wind turbines in our country is found in-------( b )
a. Ladakh
Madhya Pradesh
c.
b.
b.
energy from waste
c.
Geo thermal
electricity
II
Fill in the blanks
 The principle involved in the conversion of solar energy into electrical
energy is called
photovoltaic effect
 The conversion of crude oil from plant seeds into a useful fuel involves
process called trans esterification
 Wind energy is a converted form of
a
solar energy
 The energy trapped within 10 km of earth’s crust is known as geo thermal
energy
Q
III Answer the following
 What is the need for trapping alternative sources of energy?
We are using conventional sources of energy on a large scale. Due to this their
reserves are depleting at a faster rate. At the same time , it is becoming
increasingly difficult to discover new deposits. This led to the attempt to trap
alternative sources of energy all over the world.
 List the advantages of nonconventional sources of energy over
conventional sources.
Non conventional
Conventional
Sources
sources

Non-conventional sources
sources of
Of energy are permanent.
temporary.
 Non-conventional sources of
sources of energy
Energy are eco-friendly
friendly
 Non-conventional sources
of energy
Of are very efficient
efficient
 Almost all non-conventional
produce
Energy produce high energy.
effffect
Conventional
energy are
Conventional
non echo
conventional sources
are not
Conventional sources
Reduced energy
 Differentiate between solar collectors and solar cells.
Solar collectors
Solar cells
Solar energy on the surface
convert solar energy
Of the earth can be converted
energy.
solar cells
into electrical
Into thermal energy.
 What is bio energy ?
The process in which biological matter such as plant and plant product provide
the basis for energy and its conversion is called bio energy
 Name any two plants that are sources of bio fuel ?
The plant ‘ Jatropha’ is used to get bio energy (bio diesel )
which produces bio energy is ‘ Pongamia pinnata.
Another plant
 Write a brief note on Geothermal energy.
Geo thermal energy is one which is got from the depth of the earth. 10 km
deep into the earth , heat is available and this heat can be converted into
electrical power . The temperature of Geo thermal energy is about 1300 0 c
There are about 340 hot springs (hot water gushing out from the earth )
identified in different parts of our country. They are Puga , Manikaran,
Tatapani and Bakneshwar.
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