A charge-coupled device (CCD) is a kind of device that is widely used for such
diverse applications as computer memories and image recording. The charge-coupled
device employs an array of metal-oxide contacts, as illustrated in Fig. 14.25. Assuming a
p-type semiconductor, each of them has a positive imposed potential to create an
inversion layer just inside the semiconductor.
Scattering of electromagnetic waves
The third important phenomenon that affects wave propagation is scattering.
Scattering results from what are, effectively, elastic collisions between the photons of the
incident beam and particles or heterogeneities in the material, causing the photons to be
deflected, or scattered, so that they propagate in some new direction. Scattering subtracts
intensity from the transmitted wave and contributes to its attenuation. The material
property that governs scattering is called the scattering coefficient, S. A wave that is
transmitted through a medium with scattering coefficient, S, is attenuated according to
the relation
Optical glass and gemstones
Optical glasses serve a number of different functions. Some, like window glass,
are intended to maximize transparency. Others, like "crystal" glassware, are intended
both to reveal what is contained and to add a certain luster to it. Still other glasses are
colored, often for cosmetic reasons, but sometimes to filter light, as in tinted sunglasses
and windshields.
Ferrimagnetism
Ferrimagnetism occurs in polyatomic compounds that contain ions with different
core magnetic moments. The core magnetic moments order in an antiferromagnetic
pattern, but, since alternate moments differ in magnitude, they do not cancel. The
material has a net ferromagnetic moment.
The most important of the ferrimagnetic materials are the ferrites , which have the composition MFe2O4, where M is a divalent metal ion. The most familiar of these is magnetite, Fe3O4, which is the historic lodestone that was the first known ferromagnetic material. The ferrites crystallize in the spinel structure. While I shall not attempt to draw it here, it is a relatively simple structure that has a close-packed, FCC arrangement of oxygen atoms with metal ions in 1/2 of the octahedral interstitial sites and 1/8 of the tetrahedral sites. Since there are 2 tetrahedral and 1 octahedral void per oxygen ion, there are 2 metal ions in octahedral sites for each ion in a tetrahedral site. The magnetic order is an antiferromagnetic order in which the moments of all of the octahedral ions are oriented in one direction, while those of all the tetrahedral ions are oriented in the opposite direction.
The most important of the ferrimagnetic materials are the ferrites , which have the composition MFe2O4, where M is a divalent metal ion. The most familiar of these is magnetite, Fe3O4, which is the historic lodestone that was the first known ferromagnetic material. The ferrites crystallize in the spinel structure. While I shall not attempt to draw it here, it is a relatively simple structure that has a close-packed, FCC arrangement of oxygen atoms with metal ions in 1/2 of the octahedral interstitial sites and 1/8 of the tetrahedral sites. Since there are 2 tetrahedral and 1 octahedral void per oxygen ion, there are 2 metal ions in octahedral sites for each ion in a tetrahedral site. The magnetic order is an antiferromagnetic order in which the moments of all of the octahedral ions are oriented in one direction, while those of all the tetrahedral ions are oriented in the opposite direction.
What is Magnetostriction
Almost all ferromagnetic materials exhibit the phenomenon of magnetostriction in
which the material spontaneously expands or contracts in response to a magnetic field.
The phenomenon is due to the fact that the material can ordinarily increase its local
magnetization slightly by expanding or contracting to optimize the separation of its ion
cores. The sign and magnitude of the magnetostriction depends on the material.
Magnetostriction is a useful property that permits a time-varying magnetic field to be converted to a mechanical signal, or vice versa. It is used in transducers and in small speakers for consumer electronics, among many other applications. While nickel was the principle material of choice for early magnetostrictive devices, ferrites are often preferred today since their high resistance minimizes losses due to induced electrical currents.
Magnetostriction is a useful property that permits a time-varying magnetic field to be converted to a mechanical signal, or vice versa. It is used in transducers and in small speakers for consumer electronics, among many other applications. While nickel was the principle material of choice for early magnetostrictive devices, ferrites are often preferred today since their high resistance minimizes losses due to induced electrical currents.
The magnetic behavior of a type II superconductor
The negative interfacial tension between the normal and superconducting phases
is responsible for the unique magnetic behavior of type II superconductors. When ß < 0
the material is driven to create as much interface as possible, and can do so by spontaneously
subdividing into a two-phase mixture. The two-phase mixture persists over a
range of conditions (in our case, a range of H to either side of Hc) since the subvolumes
of the high-energy phase can be made so small that the interfacial tension dominates the
free energy. There are, however, limits on how small the regions of normal metal can be.
These set upper and lower bounds on the magnetic field that produces the mixed state.
THE CRITICAL CURRENT
ABOUT THE CRITICAL CURRENT
The current-carrying capacity of a superconductor is limited by the critical current density, jc. The critical current of a type I superconductor is set by the critical field; the current induces a magnetic field that adds to the applied field, and the total cannot exceed the critical field. In fact, this limit is not very restrictive unless the applied field is already a considerable fraction of Hc. As we show below, type I conductors can carry very high current densities without inducing fields that approach Hc. Their use in magnets and motors is restricted by the low value of Hc rather than by the field-free critical current.
The critical current of a type II superconductor is set by a completely different mechanism that may limit it to a very small value. When the conductor is in the mixed state, the current imposes a force (the Lorentz force) on the magnetic vortices that thread through it. If the vortices move in response to this force their motion produces an electrical resistance. For this reason, a pure, perfect type II conductor becomes resistive as soon as it enters the mixed state, at Hc1, and is even less useful than a type I superconductor. However, the vortices are linear features that interact with microstructural defects such as precipitates and grain boundaries. Just as microstructural defects pin dislocations and increase strength, they also pin superconducting vortices so that there is a finite critical current in the mixed state. The technologically useful type II superconductors have microstructures that are engineered to provide the strong vortex pinning needed to support high critical currents at high fields.
The current-carrying capacity of a superconductor is limited by the critical current density, jc. The critical current of a type I superconductor is set by the critical field; the current induces a magnetic field that adds to the applied field, and the total cannot exceed the critical field. In fact, this limit is not very restrictive unless the applied field is already a considerable fraction of Hc. As we show below, type I conductors can carry very high current densities without inducing fields that approach Hc. Their use in magnets and motors is restricted by the low value of Hc rather than by the field-free critical current.
The critical current of a type II superconductor is set by a completely different mechanism that may limit it to a very small value. When the conductor is in the mixed state, the current imposes a force (the Lorentz force) on the magnetic vortices that thread through it. If the vortices move in response to this force their motion produces an electrical resistance. For this reason, a pure, perfect type II conductor becomes resistive as soon as it enters the mixed state, at Hc1, and is even less useful than a type I superconductor. However, the vortices are linear features that interact with microstructural defects such as precipitates and grain boundaries. Just as microstructural defects pin dislocations and increase strength, they also pin superconducting vortices so that there is a finite critical current in the mixed state. The technologically useful type II superconductors have microstructures that are engineered to provide the strong vortex pinning needed to support high critical currents at high fields.
What is magnetic effect of electric current?
An electric current passing through the coil produces
magnetic field around it. This effect is called magnetic effect
of electric current.
State flemings night hand rule?
Arrange the first three fingers of your right hand mutually
perpendicular to each other. If fore-finger indicates magnetic
field, thumb indicates motion of conductor, then second
finger indicates the direction of induced current flowing
through the conductor.
Define Electro magnetic induction.
Rate of change of the magnetic field linked with the coil
induces on e.m.f in the coil. This is called electro magnetic
induction.
What are the uses of ultrasound waves?
1.Study of ultrasound waves through a medium reveals physical properties like elasticity, configuration of atoms.
2. Used to detect cracks and flows in metal mouldings
3. Used in mixing of immiscible liquids.
4. used in the manufacturing of alloys.
5. used in drycleaning.
6. used as insect repellants
7. used in sterilization.
8. used to cure neuralylic and rheumatic pains.
9. used in bloodless surgery.
10. used to break gallstones.
2. Used to detect cracks and flows in metal mouldings
3. Used in mixing of immiscible liquids.
4. used in the manufacturing of alloys.
5. used in drycleaning.
6. used as insect repellants
7. used in sterilization.
8. used to cure neuralylic and rheumatic pains.
9. used in bloodless surgery.
10. used to break gallstones.
What is doppler effect?
Answer: The apparent change in the frequency of a sound wave or
light wave when there is relative motion between the source
and the observe is called Doppler effect.
A. J.C Doppler discovered doppler effect
A. J.C Doppler discovered doppler effect
Why is ultrasound scanning is preferred over x-rays?
Answer: Ultrasound waves are less harmful when compared to
x-rays
Write the relation ship between speed, time and distance of sound waves.
d=vt d=distance of the object from sonar
v= velocity of ultrasound wave in water
t = time interval between transmission and
reception of ultrasound waves.
SOUND QUESTIONS AND ANSWERS
1. Why is study of sound important?
Answer:. Study of sound helps us to know how speech is produced
there by to correct speech impairment.
2. What is an echo?
Answer: A Sound heard after reflection from a rigid surface is called Echo.
3. What is Audible range?
Answer: 20 HZ to 20000HZ
4. What is infrasonic sound.
Answer: A sound of frequency less that 20HZ is called infrasonic sound.
5. What is ultrasonic sound?
Answer: A sound of frequeny greater than 20000 HZ is called ultrasonic sound.
6. Name some animals which can produce ultrasound.
Answer: Bats, Dolphines, dogs
7. Name some animals which can here ultrasound.
Answer: Bats, Dolphines.
8. Why the energy of ultrasound is high?
Answer: Because of high frequency.
9. What is SONAR
Answer: Sonar stands for “SOUND NAVIGATION AND RANGING”
10. What are the uses of sonar?
Answer: 1. To measure depth of sea.
2. To locate underwater objects.
11. Which are the two parts of Sonar?
Answer: 1. Transmitter 2. Detector
12. What is the function of transmitter in SONAR?
Answer: A Transmitter produces ultrasound waves and transmits them in to the water all around.
13. What is the function of detector in SONAR?
Answer: A detector detector the reflected ultrasound waves and coverts it to electrical signals
14. What is persistence of hearing?
Answer: The sensation of sound persists in our ear for about 0.15, this is called persistence of hearing.
15. What is the minimum distance from the obstacle to hear a clear echo?
Answer: 17m
16. When can we here a multiple echo?
Answer: If the sound reflects from the number of reflecting surface then we can hear multiple echos.
17. How do we hear thunder?
Answer: We hear thunder by the multiple reflections of sound from many reflecting surface of clouds.
18. When is sound produced.
Answer: Sound is produced by the vibration of bodies.
Answer:. Study of sound helps us to know how speech is produced
there by to correct speech impairment.
2. What is an echo?
Answer: A Sound heard after reflection from a rigid surface is called Echo.
3. What is Audible range?
Answer: 20 HZ to 20000HZ
4. What is infrasonic sound.
Answer: A sound of frequency less that 20HZ is called infrasonic sound.
5. What is ultrasonic sound?
Answer: A sound of frequeny greater than 20000 HZ is called ultrasonic sound.
6. Name some animals which can produce ultrasound.
Answer: Bats, Dolphines, dogs
7. Name some animals which can here ultrasound.
Answer: Bats, Dolphines.
8. Why the energy of ultrasound is high?
Answer: Because of high frequency.
9. What is SONAR
Answer: Sonar stands for “SOUND NAVIGATION AND RANGING”
10. What are the uses of sonar?
Answer: 1. To measure depth of sea.
2. To locate underwater objects.
11. Which are the two parts of Sonar?
Answer: 1. Transmitter 2. Detector
12. What is the function of transmitter in SONAR?
Answer: A Transmitter produces ultrasound waves and transmits them in to the water all around.
13. What is the function of detector in SONAR?
Answer: A detector detector the reflected ultrasound waves and coverts it to electrical signals
14. What is persistence of hearing?
Answer: The sensation of sound persists in our ear for about 0.15, this is called persistence of hearing.
15. What is the minimum distance from the obstacle to hear a clear echo?
Answer: 17m
16. When can we here a multiple echo?
Answer: If the sound reflects from the number of reflecting surface then we can hear multiple echos.
17. How do we hear thunder?
Answer: We hear thunder by the multiple reflections of sound from many reflecting surface of clouds.
18. When is sound produced.
Answer: Sound is produced by the vibration of bodies.
Define the 5 stages of working petrol engine.
a. Intake stroke:- The vapourised mixture of petrol and air is let in through the inlet value. The outlet value remains closed. Piston moves away from the spark plug.
B. Compression stroke:- Both the values are closed and the mixture of air and petrol is compressed by the piston moving towards the spark plug. Though the compression increases the temperature of the mixture it is not sufficient to ignite the petrol.
c. Power stroke:- The ignition stage and the expansion stage are together called power stroke.
d. Exhaust stroke: Here outlet value opens Piston moves back. The products of combustion gases are pushed out of the cylinder through the exhaust value.
B. Compression stroke:- Both the values are closed and the mixture of air and petrol is compressed by the piston moving towards the spark plug. Though the compression increases the temperature of the mixture it is not sufficient to ignite the petrol.
c. Power stroke:- The ignition stage and the expansion stage are together called power stroke.
d. Exhaust stroke: Here outlet value opens Piston moves back. The products of combustion gases are pushed out of the cylinder through the exhaust value.
Define the function of Petrol engine.
Spark plug:- The compressed air and petrol mixture is ignited by the sparks produced by the spark plug.
Crank shaft:- crank shaft coverts linear movement into cirular motion.
Carburettor:- In the carburettor petrol and air are mixed in proper proportions.
Outlet valve:- makes the spent gases to go out of cylinder.
Crank shaft:- crank shaft coverts linear movement into cirular motion.
Carburettor:- In the carburettor petrol and air are mixed in proper proportions.
Outlet valve:- makes the spent gases to go out of cylinder.
Define the function of Crank shaft.
Crank shaft coverts linear movement into circular motion.
The wheel of the crank shaft makes half rotation during
the expansion stroke.
QUESTIONS RELATED TO HEAT
1. What is heat engine?
A heat engine is a device which converts heat energy into
mechanical energy.
2. Name the two types of heat engine.
a. External combustion engine
b. Internal combustion engine.
3. What is the effect of heat?
a. Increase in the temperature of a body.
b. Expansion of the body
c. change of state of matter
d. chemical change in the body
A heat engine is a device which converts heat energy into
mechanical energy.
2. Name the two types of heat engine.
a. External combustion engine
b. Internal combustion engine.
3. What is the effect of heat?
a. Increase in the temperature of a body.
b. Expansion of the body
c. change of state of matter
d. chemical change in the body
QUESTIONS RELATED TO WAVES
1. What is amplitude of a wave?
The maximum displacement of a particle form its mean position is called amplitude of a wave.
2. What are electromagnetic waves ?
The waves which don’t need material medium for their propagation, produced by an acceleration of an electric charges are called Electromagnetic waves.
The maximum displacement of a particle form its mean position is called amplitude of a wave.
2. What are electromagnetic waves ?
The waves which don’t need material medium for their propagation, produced by an acceleration of an electric charges are called Electromagnetic waves.
QUESTIONS AND ANSWERS RELATED TO MOTION
1. What is simple harmonic motion? Give an example.
The motion which repeats after regular intervals of time is called simple harmonic motion.
2. What are the uses of studying wave motion?
Study of wave motion helps us to why microwaves are used in ovens and how radio waves are used in radio stations etc.,
3. Write any two applications of studying simple harmonic motion.
1. Simple harmonic motion of a pendulum was used for the measurement of time.
2. Tuning the musical instrument is done with the vibrating tuning fork which executes simple harmonic motion.
The motion which repeats after regular intervals of time is called simple harmonic motion.
2. What are the uses of studying wave motion?
Study of wave motion helps us to why microwaves are used in ovens and how radio waves are used in radio stations etc.,
3. Write any two applications of studying simple harmonic motion.
1. Simple harmonic motion of a pendulum was used for the measurement of time.
2. Tuning the musical instrument is done with the vibrating tuning fork which executes simple harmonic motion.
What are mechancial waves?
Give an examples.
The waves which need material medium for their propagation
are called mechanical waves for their propagation are called
mechanical waves.
Example: Sound waves
Example: Sound waves
Write any two characteristics of wave motion?
The two characteristics of wave motion are
1. A wave is produced by a periodic disturbance.
2. When a wave propagates in a medium the particles vibrate afont their mean position and ernergy is transferred without the transfer of the particles of the medium.
1. A wave is produced by a periodic disturbance.
2. When a wave propagates in a medium the particles vibrate afont their mean position and ernergy is transferred without the transfer of the particles of the medium.
What are transverse waves?
After The waves in which particles of the medium vibrate
perpendicular to the direction of motion.
Example. Electromagnetic waves.
Example. Electromagnetic waves.
What are longitudinal waves?
The waves in which particles of the medium vibrate parallel
to the direction of motion.
Example. Sound waves
Example. Sound waves
What are waves?
The disturbance set up in a medium is called as a wave.
The two types of wave are 1.Mechanical waves. 2.Electromagnetic waves.
The two types of wave are 1.Mechanical waves. 2.Electromagnetic waves.
Which places in India are suitable to install the plants which covert wave energy in to electrical energy?
The tropical coastline of our country, especially the south
west coast line, is found to be highly suitabale for
establishing energy conversion plants.
ONE MARK QUESTIONS -SCIENCE
1. What are the limitations of wind energy?
* It cannot be installed everywhere.
* Wind speed is not same through out the year.
2. Where do you find the largest collectors of wind mills in India?
Near Kanyakumari in Tamil Nadu.
3. What should be the speed of wind to convert it in to electrical energy?
The speed of wind should be between 8 and 22 m per sec.
4. What are wind mills?
The devices which convert wind energy in to electrical energy called wind mills.
5 . How is electricity generted from wind energy?
The Kinetic energy of the wind is utilized to rotate wind mils which converts wind energy into electrical energy.
* It cannot be installed everywhere.
* Wind speed is not same through out the year.
2. Where do you find the largest collectors of wind mills in India?
Near Kanyakumari in Tamil Nadu.
3. What should be the speed of wind to convert it in to electrical energy?
The speed of wind should be between 8 and 22 m per sec.
4. What are wind mills?
The devices which convert wind energy in to electrical energy called wind mills.
5 . How is electricity generted from wind energy?
The Kinetic energy of the wind is utilized to rotate wind mils which converts wind energy into electrical energy.
BIO ENERGY RELATED QUESTIONS
1. What is bio-energy?
Energy produced by the biological matter is called bioenergy.
2. How is bio energy advantageous?
* It offers clean fuel for energy.
* It maintains an unpolluted environment and reduces the carbondioxide content in the atmosphere.
3.. Write any two plants which are directly or indirectly used to prepare biodiesel.
* Jatropha
* Pongamia Pinnata (Honge
Energy produced by the biological matter is called bioenergy.
2. How is bio energy advantageous?
* It offers clean fuel for energy.
* It maintains an unpolluted environment and reduces the carbondioxide content in the atmosphere.
3.. Write any two plants which are directly or indirectly used to prepare biodiesel.
* Jatropha
* Pongamia Pinnata (Honge
What are solar collectors?
The devices which convert solar energy into thermal energy
and stores them are called solar collectors.
Example. Solar, Cooker, Solar pond.
Example. Solar, Cooker, Solar pond.
What is Solar Energy? How it reaches the earth? What is the cause of Solar energy?
The energy obtained from sun in the form of heat and light
is called solar energy. Continuous thermo nuclear fusion
reaction taking place inside the sun, this is the source of
solar energy. Solar energy reaches earth in the form of
electromagnetic radiations.
What are renewable sources of energy?
Resources which are not exhausted even after continues
use and can replenished quickly in nature are called
renewable or inexhaustible resources.
Ex: Solar Energy, air, water, soil, forest, wild life.
Ex: Solar Energy, air, water, soil, forest, wild life.
What are the non-renewable sources of energy? Give two examples
Resources which are exhausted after continuous use and
take a long time to replenish are called non renewable or
exhaustible resources.
How are Mongoloids different from caucasoids?
Cancasoids
Mongoliods
- light skin, blue or dark brown eyes
- high ridged nose
- with narrow nostrils
- hair is straight or wavy
- live in Europe, India & America
Mongoliods
- yellowish or reddish skin
- fairly thick lips and wider nose
- hair is straight.
- live in China, Japan, Mongolia, Malaysia also includes, Eskimos &American Indians
Write the differences between cromagnon man and modern man
Cromagnon man had a large stature. He was active and
intelligent. +e used finely chipped stone arrows and spear
points and was able to tame animals.
But modern man is culturally very much advanced. He is
capable of thinking ,memorizing, speaking, reading and
writing. Also he has developed science and technology using
his intelligence.
Write the abilities of Zinzanthropes form of pre-humans?
Zinnanthropus type of humans had stronger and straighter
legs and upright posture was possible. This form could
focus its eyes on objects which it could hold, it was also
able to manipulate objects with the help of flexible hands.
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