VALUE BASED QUESTIONS CLASS XII.docx

8/9/2019 VALUE BASED QUESTIONS CLASS XII.docx

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Value based questions for class 12(Prepared by group 2)

ELECTROT!T"C1)An elderly woman went alone to the electricity office to change the name of her electricity

connection in his sons favour. When she enquired in the office she was asked to get a photocopy of

the relevant document which works under electrostatic induction. The photo copy op was far away

and across the road. She took the help of the passer-by and got her photocopy done.

a) what values did the passer-by have

b) !ow does a neutral body get charged by electrostatic induction

!ns#a) $elping% s&aring% respect for elderly people#

b) 'or a body to get positiely c&arged% a negatiely c&arged body &as to bring close to t&e

neutral body &ic& after eart&ing gets c&arged unifor*ly.

2)"n a fair a child was troubling his parent and crying for something. #n seeing this$ a young boywent to the child and said that he would perform a trick with balloons. !e took two balloons and

inflated them and after rubbing with the sweater he sticks the balloons with walls. The child en%oyed

this activity$ and stopped crying.

a) &ive two values of the young boy

b) !ow did the balloons get attracted Will they repel also

!ns# a) Presence of *ind% concern and sy*pat&y

b) +&en balloons ere rubbed it& oollen seater% it beco*es negatiely c&arged# +&en

ta,en nearer t&e all% positie c&arges are induced by electrostatic induction on t&at

part of t&e all% so gets attracted# -es% &en t&e bodies are si*ilar c&arged t&ey

repel#

.)Sushil had to repaint his car when he was reminded by the car company for his regular car service.

!e told them to do spray painting of steel grey colour. The company also replied that they usually

perform spray painting only as wastage is minimi'ed and even painting achieved

a) what values did the car service company have

b) "f spray painting is done by electrostatic induction$ how is even painting achieved

!ns# a) Custo*er care% co**it*ent% concern and trut&fulness

b) /roplets of paint are c&arged particles &ic& get attracted to any *etallic ob0ects by

electrostatic forces#

)"n (amans grandfathers room the fan was running very slowly. )ue to which he was sweating and

was restless. !e wanted to rectify this. !e called for an electrician who came and changed the

capacitor only after which the fan started running fast.

a) What values did (aman and his classmates have

b) What type of energy is stored in the capacitor and where

!ns a) concern% respect to elders and responsibility#

b) Electrical energy in t&e dielectric of t&e capacitor#


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!ns a) !areness ; sensitiityb) 'rictional electricity and electric disc&arge#

1RRE=T ELECTR"C"T-12)#ne night before eams (aman was preparing for his physics eam. Suddenly the light in hisroom went off and he could not continue his studies. !is cousin brother 4arun who had come to visit

him was quick to react. 4arun using the torch installed in his mobile phone found that the fuse had

blown out. !e checked the wiring and located a short circuit. !e rectified it and put a fuse wire.The

light came to life again. (aman head a sigh of relief thanked 4arun and continued his studies.

a)What are the values pro%ected by (aman and 4arun :Any two;

b)Why did 4arun have to check the wiring

c)What is an electric fuse What characteristics you would prefer for a fuse wire

!ns

(a) Ra*an ac,noledging t&e &elp fro* ot&ers it& gratitude#(b) Varun aareness of t&e tec&nology% &elping tendency% practical ,noledge of t&e

sub0ect#

(c)!n electric fuse is a ire used as a safetydeice &ic& *elts &en current e4ceeds

t&eli*it#Lo *elting point% &ig& resistiity

1.)


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a)What are the values displayed by the friends

b)"n which unit electric meters readings counted

!ns

a) $onesty% s&aring of ,noledge% illingness to &elp

b) ?+&

1)Atul is lives in an area where birds in large groups play around producing pleasing humming

sounds. #ne day he notices that the high power lines soon after a strong wind have come too close

which may prove fatal for the birds that would sit on them and flutter their wings for some reason or

other. !e complained to the authorities and the lines were set at the proper distance once again.

(a)What are the values possessed by Atul and the authorities :Any two;

(b)What is the danger that could happen to the innocent birds in Atulss view

(c)!ow did distancing the lines solve the problem

!ns

a) !ffection toards birds% ta,ing appropriate action %duty conscious

b) T&e bird *ay get electrocuted

c) !oid spar,ing

13)Su%ata was doing an eperiment :8omparison of emfs; using potentiometer in +hysics lab. She

could not take the readings because the galvanometer showed same side deflection. She checked the

8ircuit and the connections were correct. !er friend *anisha who was doing her eperiment nearby

came to help Su%ata. *anisha increased the voltage of the eliminator :by turning the knob; supplying

current to the potentiometer. Su%ata tried the eperiment again and got the readings. She thanked

*anisha for her help.

a) What are the values displayed by both Su%ata and *anishab) State one reason why the galvanometer showed same side deflection.

c) )istinguish between emf and terminal pd.

Ans>

a) &aring of ,noledge% caring for and &elping ot&ers#

b) T&e e*f of t&e driing cell s&ould be greater t&an t&e e*f of t&e e4peri*ental cells#

c) e*f T&e potential difference beteen t&e ter*inals of a cell &en t&e cell is in t&e open

circuit

Ter*inal pdt&e potential difference beteen t&e ter*inals of a cell &en t&e cell is in

t&e closed circuit#

15)ather and a son returned home completely drenched due to heavy rain. ather advised his son not

touch any electrical units with wet hands for he may get a shock7 "n spite of this$ on immediately

entering the house$ the son switches on the light :supply voltage is ??3 4; and gets a severe shock7

!e was fortunate not to get electrocuted. ather$ who is a 1iologist$ told that when the skin is dry$

resistance of a human body is =3@7 and when the skin is wet the body resistance is =@33 .

a)What is the lesson learnt by you

b)8alculate the current that flow through :"; a wet body and :ii; a dry body.

c)When will we have serious consequences and why

!nsa) To obey elders6

b) >sing% " @ VAR (i) 17 *!6 (ii) 2#2 *!#6

c) +et body it& 17*!% &en t&e current flos% t&e result is fatal


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B!=ET"C E''ECT O' ELECTR"C C>RRE=T !=/

B!=ET"B

17)*r S.


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used on this stove. She took the instruction manual and eplained to her mother$ that the stove works

on magnetic induction$ and copper being a dia magnetic material$ will not respond to it.

a) What values did *r 4aradan and )hanya ehibit towards *s Sumathy *ention any

two.

b) &ive an eample of diamagnetic material

!ns#a) aareness% concern for conseration of energy and fossil fuels% s&aring t&e ,noledge)

b) Copper

21)1ala and (ama class 9"" students$ were assigned a pro%ect based onmagnetism. "n their pro%ect

work$ they had calculated the value of earthDsmagnetic field. When they submitted their pro%ect for

verification.*r Santosh$ their physics teacher$ corrected the mistakes. !e alsosuggested few books

which could be of use to them.

a) =.What values did *r Santosh ehibit towards his students *ention anytwo

b) ?.*ention the three magnetic elements required to calculate the value ofearth and draw a neat

diagram to eplain them.

!ns

a) $onesty% &elpfulness% responsible be&aiour toards students% concern for t&e student to

create interest in t&e sub0ect)

b) Bagnetic declination% *agnetic inclination and &oriDontal co*ponentof eart&s *agnetic

field#

22)*r 4asudev the chief development officer$ in southern railway went on anofficial tour toattend a

seminar on fast moving trains. !e met his friendin Tokyo after he finished his seminar there. !is

friend eplainedto4asudev$ how Bapanese people are concentrating on energy conservationand saving

of fossil fuels using *aglev trains. *r4asudev travelled fromTokyo to #saka in maglev train and

found that sound is less$ traveling issmooth and understood how can we improve mass transporting

systems.

a) What values did *r 4asudev found from his friend *ention any two.

b) ?.#n which principle does it work

!ns#

a) !areness about ne tec&nology% concern for energy conseration% decreaseof noise pollution and air pollution i#e% concern for eniron*ent)

b) +&en a superconductor is cooled in a *agnetic field belo its criticalte*perature t&e

*agnetic field lines are e4pelled s&oing dia*agneticproperty# T&is is called Beissner

effect#

2.)*s Eavanya a house wife aged F3 years complained of stomach ache oneday. !er husband *r

Srinivas took her to a nearby hospital. The doctorobserved her and found something wrong near her

liver and suspectedmalignancy. There after checking her *(" scan$ a team of doctors advised

her to go through 8arbon radio therapy which is very safe. They said usingcyclotron$ high speed ions

can be generated that directly attach thecancerous tissues and destroy them.

a) What values did *r srinivas and the doctor have ehibited *ention anytwo.

b) ?.What are the role played by ,lectric field and magnetic fielding 8yclotron


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!ns#

a) !ns#concern for ot&ers% &elpfulness% presence of *ind% responsible citiDen

b) T&e c&arged particles are accelerated by t&e electric field it& t&e*agnetic field bringing

t&e* again and again to t&e electric field t&atis t&e region beteen t&e /ees#

2)A person entering the airport was asked to remove the contents from his pant and shirt pockets7 his

hand bags and luggage were also checked by airport authorities by using a metal detector. "mran got

annoyed and argued with the airport authority as to the reasons for such procedure. The authority tells

him that all the passengers and their belongings will be checked for security check to ensure safe

travel.

a)What is the value that imparts us in the above scenario

b)1riefly eplain the working principle of a metal detector.

!ns a) respecting la and obeying t&e rules enacted by t&e nation6 self discipline and aoiding

argu*ents%

b) c&ange in t&e *agnetic field in a *etal detector due to t&e *etals carried by t&e contents of

c&ec,ing &ic&% induces c&ange in current in t&e coil of t&e *etal detector# T&is

detection of c&ange sets up an alar*)

23)Two girls An%ali and 1abita were very good observers and performed in the school function using

their cassette player. #ne day when they were performing$ tape got stuck up and the music stopped.

1ut An%ali was determined not to let down the performance so she sang the song instead of dancing

and 1abita completed the dance.

a) What were the values displayed by An%ali and 1abita

b) What kind of material is using for coating magnetic tapes used in cassette players or building

memories stories in modern computers

!ns#

a) Tea* spirit% confidence% deter*ination and courage

b) 'erro*agnetic *aterials#

25)Sumit was using a galvanometer in the practical class. Gnfortunately it fell from his hand and

broke. !e was upset$ some of his friends advised him not to tell the teacher but Sumit decided to tell

his teacher. Teacher 4imla listened to him patiently and on knowing that the act was not intentional$

but %ust an accident$ did not scold him andused the opportunity to show the internal structure of

galvanometer to the whole class.

a) What are the values displayed by Sumit

b) What is the principle of moving coil galvanometer

!ns#a) Courage to tell t&e trut&% ratitude to &is teac&er for &er patience and tolerance

b) Torque on current carrying coil placed in *agnetic field#


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ELECTROB!=ET"C "=/>CT"O= !=/

!LTER=!T"= C>RRE=T27)


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!ns#

a) an inductor and a capacitor

b) Resonance#

c) Concern for social security#

.1)A visit to science ehibition was arranged for class 9"". They saw theprocess of electroplating.The students ehibited the electro platingwith the help of )8 source. "mmediately students raised the

doubt$ why dont we use A8 instead of )8 The teacher in chargeeplained and cleared their doubts.

Huestions>

a) What value was displayed by these students

b) Why should we use dc instead of ac

!ns#

a) Curiosity% critical t&in,ing and understanding

b) Fecause in !C% direction of current c&anges periodically &ereas t&eelectrodes are it&

fi4ed polarities#

.2) Subhash wanted to see the work of a transformer. !e bought atransformer from a shop. !e

connected the primary to an A8supply. At that time an aluminium ring in his hand falls into the coreof

the transformer. Without noticing that he switched on the powersupply. The aluminium ring flew up

into the air. !e became panic. !isfather$ an electrical engineer eplained the reason.

a) What value does he ehibit

b) 1ring out the reason for the above activity.

!ns#

a) Curiosity%

b) "nduced current in t&e alu*iniu* ring acts in t&e opposite directionto t&ose in Coil and so

*agnetic field of t&e ring repels t&e *agnetic field due to

t&e coil!s a result of it t&e ring s&oots in air#

..)(a% is in 9"" standard. !is +hysics teacher demonstrated aneperiment to eplain aradays laws

of electromagnetic induction. (a% interrupted her lecture and asked$"s there any possibility ofinduced

emf due to earths magnetism The teacher was stunned fora moment and gave this question for group

discussion. inally thestudents came out with correct answer.

a) Write the values that you learnt from this incident.

b) What can be reason for (a%IDs question!ns#

a) Tea* spirit% curiosity

b)+&en t&e ire in =9 direction is dropped freely% none of t&eco*ponents of eart&GHs *agnetic

field is intercepted#o no induced e*f is produced# +&en t&e +ire is dropped freely in E+

direction &oriDontal co*ponent of eart&GHs *agnetic field isintercepted# o e*f is induced in t&e

coil#

.)"sabella used an induction stove and eplains to her neighbour that due to shortage of E+& one

must utili'e other sources that are available to produce heat energy7 being a +hysics teacher "sabella$

eplains that the #il companies are trying their best to meet the demands for E+& and that as a good

citi'en one must use other sources wherever feasible. "sabella uses an induction stove having a value

of C! inductor and the flow of current is from =3Ato CA in J =3-?seconds.


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a) "n the above$ what is the quality you find in the +hysics teacher

b) 8alculate the emf generated in the above

!= a) concern for t&e nation% cost econo*ic attitude% s&aring ,noledge

b) e @ 9L d" A dt% @ 2..#.V

.3)Two friends (am and Shyam have been assigned a work to choose a step down transformer forsupply of power for a small town with a demand of = *W at ??34 situated ?3km away from an

electric plant generates power at FF347 the resistance of the two line wires carrying power is

3.@ohm5km7 two step down transformers are available- F3334-??34 0 =333334 K ??34. (am has

chosen =333334-??34 step down transformer.

a) As a student of physics$ which step down transformer will you prefer for supply of a power for

a small town. &ive reason.

b) What are the values associated with the above decision

!ns

a) &ya* go it& Ra*s option% because Poer loss is less in 1


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.8)Akhil was playing cricket with his friends$ when a ball hit his friend 1harat on his left leg .1harat

screamed with pain.Akhil rushed towards him and comforted him and asked him not to move hisleg.

!e quickly took out his cell phone and called up 1haratIDs parents andbriefed them about the incident.

"n=3 minutes 1harat was taken to thenearby hospital and was eamined by the doctor who advised for

an 9-raystest which confirmed a hairline fracture.

a) !ow are 9-rays producedb) *ention one another application of 9 rays.

c) *ention two qualities of Akhil which are reflected from theabove situation.

!ns#

a) I9 rays are produced by bo*barding a *etal target by &ig& energyelectrons#

b) To study t&e crystal structures

c) Presence of *ind% alertness% ta,ing initiatie% &elpful% caring#

.:)8hirag was at the restaurant chatting with his cousins. The restaurantwas clean and free of flies

and insects to his relief. !is cousin wascurious to know about the uv lamp in the corner and asked

8hirag aboutit. 8hirag eplained that inside the fluorescent lamp$ the electrical energyis converted into uv radiation. The inside of the tube is coated with afluorescent powder which

absorbs the G4 and emits violet light in thevisible region. These attract the insects which are

electrocuted by high voltagewires near the lamp$ so that they donIDt fall on the food andcontaminate

them.

i; 6ame the main source of uv rays

ii;Why are they considered harmful to us

iii;What impressed you about chirag

!ns#i) un is t&e *ain source of u rays#

ii)T&ey can cause s,in cancer &en e4posed for a longer ti*eiii) Clarity in e4plaining% &ealt& aareness% ,noledge#


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Speaker =-,lectromagnetic radiations play an important role inmaintaining the earthIDs warmth or

average temperature throughgreenhouse effect. These radiations trap the greenhouse gases suchas

8#?and water vapour thus increasing the temperature.

Speaker ?- We could reduce the emission by using solar operatedvehicles or cycles for short distance$

use public transport$ car pooing.

SpeakerQ-The government can impose carbon ta- i.e. taing theindividual and industries based on thesi'e of the 8#?emission.

a) What type radiation is speaker= referring to

b) 6ame one electronic device which emits this radiation.

c) What values do the speakers ehibit in their discussion

!ns#

a) "nfra9red radiation

b) Lig&t e*itting diodes

c) Concern about t&e eniron*ent% recognising ones duty and ta,ingstoc, of t&e

situation%open to ne ideas% scientific aareness% co**unityserice#

2)A woman and her daughter were in the kitchen$ preparing dinner using the new microwave oven

purchased last evening. Suddenly$ the daughter found that inside the microwave oven a metallic

container had been kept to cook vegetable. She informs her mother that no metallic ob%ect must be

used while cooking in microwave oven and eplains the reasons for the same.

a) What attitude of the daughter inspires you

b) &ive another use of a microwave oven

c) The frequency of microwave is Q =3==!'. 8alculate its wavelength.

!ns

a) Presence of *ind% ?noledge of sub0ect6

b) >sedin teleco**unication6 ; c) J@ cAK @ (. 4 1


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OPT"C

7)A child is observing a thin film such as a layer of oil on water show beautiful colours when

illuminated by while light. !e feels happy and surprised to see this. !is teacher eplains him the

reason behind it .The child then gives an eample of spreading of kerosene oil on water to prevent

malaria and dengue.

a) What value was displayed by his teacher

b) 6ame the phenomenon involved

!ns#

a) Value appreciation of =ature% aareness

b) "nterference of lig&t#

8)6eha is using yellow light in a single silt diffraction eperiment with silt width of 3.2 mm. The

teacher has replaces yellow light by -rays. 6ow she is not able to observe the diffraction pattern. She

feels sad. Again the teacher replaces -rays by yellow light and the diffraction pattern appears again.

The teacher now eplains the facts about the diffraction

a)Which value is displayed by the teacher

b)&ive the necessary condition for the diffraction.

!ns#

a) Botiation

b) !s t&e aelengt& of 49rays is *uc& s*aller t&an t&at of yello lig&t% so t&e diffraction

pattern is lost &en t&e yello lig&t is replaced by 49rays#

:)Aayush was watching a program on the topic *##6 on the )iscovery channel. !e came to know

from the observations recorded from the surface of *oon that the sky appears dark from there. !e got

surprised and wanted to know the reason behind it. !e discussed it with his friends$ and they told the

reasons

a) 6ame the value that was displayed by Aayush

b) &ive reason by sky appeared dark at moon.

!ns#a) curiosity

b) =o at*osp&ere at *oon &ence no scattering of lig&t#

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33)The whole class was ecited as they were on their way to


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!ns#

a) obeying road rules% alertness% concern in ot&ers life% clarity of,noledge#

b) /ue to superposition of incidentand reflected aes of &ite lig&tby t&in fil*

("nterference)

3:)(a%at and 4ikas were going to their friends house by walk. "t was asunny day in the afternoon. "twas very hot. (a%at was finding it verydifficult to see around him. !e had to strain his eyes to see.

Suddenly$4ikas took his cooling glasses from his pocket and asked him to wearthem and later$ (a%at

slowly managed to see. 4ikas advised (a%at onthe necessity of wearing sun glasses during summer

season.

a) What are the values shown by vikas

b) 6ame the phenomenon based on which cooling glasses reduce theglare.

c) What is the resultant intensity of light if both polariser andanalyser are rotated through

same angle

!ns#

a) caring %s&aring%concern

b) polarisation#

c) no c&ange in intensity of lig&t

5


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/>!L =!T>RE O' B!TTER !=/ R!/"!T"O=51). "n a multi-storeyed building$ once a fire broke out at midnight due toelectrical short circuit. (avi

along with others rushed to the spot$ informedthe fire survive and put off the fire. 1ut by that time a

huge amount ofdamage had already been done. (avi being Secretary of the building decidedto fi fire

alarms :using photo cell; in all the floors

a) What values were shown by (avi in this situation

b) #n what principle fire alarm works

!ns#

a) Concern for society% social responsibility% application of ,noledge#

b) 'ire alar* or,s on t&e principle of p&otocell#

52). )avisson and &ermerOs actual ob%ective was to study the surface of apiece of nickel by directing a

beam of electrons at the surface and observinghow many electrons bounced off at various angles.

Though the eperimentwas conducted in a vacuum chamber. air entered the chamber$ producingan oide film on the nickel surface. When they started the eperiment againand the electrons hit the

surface$ they were scattered by atoms whichoriginated from crystal planes inside the nickel crystal.

)avisson and&ermerOs accidental discovery of the diffraction of electrons was the firstdirect evidence

confirming de 1roglieOs hypothesis that particles can havewave properties as well.

a) What can we infer about the values shown by )avisson and &ermer

b) Write the epression to find the wavelength of an electron when accelerated through a

potential difference of 4volts.

!ns#

a) Perseerance% not giing up and patience

b) J@h

2meV

5.). (avi$ while returning home from office late night$ saw a person%umping into a house .Suspecting

him to be a thief$ he slowly followedhim. !e saw an alarm fied at the entry of the house.

"mmediately toalarm the people at the house$ he used his laser torch to activate thealarm$ as it works

with the visible light. The circuit became completeand siren started working and people at the house

got up and caughtthe thief. They thanked (avi for his action.

a) What moral value can you see in (avi

b) The photoelectric cut off voltage in a certain eperiment is [email protected] is the maimum kinetic energy of the photoelectrons emitted

!ns

a) Presence of *indA ocial responsibilityA attitude to &elp ot&ers#

b) ?#E#@eV% e@1#5M1


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every counter and gave the coordinator the eact number of people inthe auditorium.

a) What moral values can you see in 4ikram

b) What is photo electric effect

!ns#

a)Proper application of ,noledgeA concern for &is bossA presenceof *ind

b)P&otoelectric effect (define)

53). A function was arranged in the school auditorium. The auditorium has the capacity of F33

students. When entry started students entered in groups and counting becomes a great problem. Then

science students took responsibility at the gate. All the students entered the hall one by one. This

helped them to maintain discipline and counting became easy with the help of a device used by these

students.

a) What value is displayed by science studentsb) 6ame the device which is based on application of photoelectric effect.

!ns#a) ense of responsibility#

b) P&oto cell#


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!TOB ; =>CLE"

55)Shyam saw his younger brother wondering with a question which dealswith emission of light froma vapour lamp. !e was anious to know howdifferent colours were being emitted by different light.

!e also saw mercuryand sodium vapour lamps in the physics lab and was curious to know what

is inside the lamps. #n seeing his aniety to know more about it Shyameplained about absorption of

energy and reemission of photons in thevisible region. !e also advised him not to touch or break any

items in thelab for the thirst of knowledge.

a) What is the moral you derive from Shyam

b) Which series in the hydrogen spectrum is in the visible region

!ns#

a) Concern for &is brot&erA care about t&e sc&ool property#

b) Fal*er#

57)2 year old Bason and his father were waiting to board a bus at the busstop on a hot scorching

summer day. Bason was feeling faint with thirst andthe heat. !is anious father asked the nearby

person for water. #n seeingthis$ a tender coconut vendor gave a tender coconut to Bason who drank it

and felt better. 1oth father and son thanked the coconut vendor whorefused to take money.

a) What are the qualities that you would associate with coconut vendor

b) 6ame the nuclear reaction taking place in the sun.

!ns#

a) +ar* &earted% caring for fello*en% resourcefulness#b) =uclear fusion#

58)Ashutoshs uncle who was a kabadiwalah was getting weak day by day. !is nails were getting

blue$ he stated losing his hair. This happened immediately after he purchased a big container of heavy

mass from )elhi Gniversity 8hemistry )epartment. )octors advised him hospitali'ation and

suspected he has been eposed to radiation. !is uncle didnt know much about radiations but

Ashutosh immediately convinced her uncle to get admitted and start treatment.

a) What according to you are the values utili'ed by Ashutosh to convince his uncle to get

admitted in hospital

b) 6ame the radioactive radiations emitted from a radioactive element.!ns#

a) Value displayed 9 aareness% critical t&in,ing% decision *a,ing

b) I ray and a**a rays#

5:)+ratikshas grandfather was reading article is newspaper. !e read that after so many years of

atomic bombing in !iroshima or 6agasaki$ Bapan 6ational census indicated that children born even

now are genetically deformed. !is grandfather was not able to understand the reason behind it. !e

asked his &randdaughter +ratiksha who is studying in class 9"" science. +ratiksha sat with her

grandfather and showed him pictures from some books and eplained the harmful effects of

radiations.

a) What are the values5 skills utili'ed by +ratiksha to make her grandfather understand the

reason of genetically deformity


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b) 6ame the nuclear reactions that occurred in atom bomb.

!ns#

a) y*pat&y% co*passion

b) =uclear9 fission reactions

7


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EB"CO=/>CTOR /EV"CE

71)+rakash finds his friend (akesh connecting his new television set directly toswitch board. +rakash

advises (akesh not to do so and to connect thetelevision through a voltage stabili'er.

a) "dentify the diode used in voltage regulator.b) b;What values did +rakash ehibit in the situation described

!ns#

a) Nener diode#

b) $elpful and concerned% Practical application of t&eoretical ,noledge#

72)Ashwin was given Q semiconductors A$ 1 and 8 with respective band gaps ofQe4$ ?e4 and =e4 for

use in a photodetctor to detect R =F33nm. !e foundthat the photo detector was not working with

these semiconductors and did notknow why. !is friend Akash found out the reason for it and

eplained it to him.

a) Why did the photodetector not work

b) What according to you are the values shown by Akash

!ns#

a) Fecause energy of t&e gien aelengt& is less t&an 1 eV# $ence it does not or,#

b) $elping tendency% Presence of *ind% $ig& degree of aareness%Concern for &is friend#

7.),trinsic semiconductors are preferred over intrinsic semiconductors in most ofthe important

electronic devices.a) 6ame the ? types of etrinsic semiconductors.

b) *ention some values that can be imbibed into our lives from theproperties of etrinsic

semiconductor.

!ns#

a) p9type se*iconductor % n9type se*iconductor

b) Tea* or,% !ccepting diersity#

7)A semiconductor device is used as a rectifier that allows the ,* to flow in positive direction and

a very small value in the reverse direction. 6ow days$ there is a problem of supply of less voltage that

damages the house hold appliances. (amesh looked for the technique to save the appliances in use

a) What are the values displayed by (amesh

b) What can be the choice of device to control the input voltage to save your appliances from

damage

!ns#

a) Critical t&in,ing % $ope for i*proe*ent by loo,ing for alternaties #

b) Nener diode#


23/23

23

COBB>="C!T"O= -TEB

73)Anvita was watching her favorite T4 serial suddenly the picture started shaking on T4 screen. She

asked her brother to check the dish antenna. !er brother found no problem in dish. 8hitra noticed the

same problem in T4 picture again after some time. At the same time she heard the sound of low flying

air craft passing over their house. She asked her brother again. !e eplained the cause of shaking

picture on T4 screen when air craft passes over head.

a) 6ame the values used by Anvitas brother

b) Why the picture on the T4 screen was shaking when air craft was passing over head

!ns#

a) Critical t&in,ing and proble* soling

b) Lo lying air crafts reflect TV signals# /ue to interference beteen direct signalreceied by antenna and reflected signal t&e picture on TV s&a,es #

75)&roup discussion was arranged in class 9"" on the topic atmosphere. Three groups were made.Teacher asked the Huestion. LWhy can moon be not used as a communication satelliteM Answers

were given by all the three groups. ,ach group can give only one reason. Teacher told them that

reason givenby each group is correct. The groups collected all the three reasons and come to correct

conclusion.

a) What values were shown by all the three groups

b) &ive the correct reason for the above question.

!ns#a) Frot&er&ood% tea* spirit% critical t&in,ing #

b) Boon is not a geostationary satellite#

77)Surabhis uncle wants to talk to his son in GSA. !e does not have much money to spend on

telephone calls. !e has a computer at his home. Surabhi told her uncle that he can talk to his son with

the help of computer and told him about internet. !er uncle now talks to his son every day. !e

thanked Surabhi for giving useful advice.

a) What according to you are the values displayed by Surabhi

b) !ow does internetwork

!ns#a) Caring% creating aareness#

b) Principle of teleco**unication#

Documents

VALUE BASED QUESTIONS CLASS XII.docx