s.4 phys ex q (singa)

8/20/2019 S.4 Phys Ex Q (Singa)

1/17

MORLEY SENIOR HIGH SCHOOL

YEAR 11

PHYSICS (UNIT 2B)

SEMESTER 2: EXAMINATION 2009

Student! N"#e: Tut$%&"' G%$u:

Te"*e%! N"#e: +"te:

_____________________________________________________________________________________

TIME ALLOWED FOR THIS EXAMINATION PAPER:

Reading time: 10 minutes

W!"ing time: # $u!s

T$is %uestin & ans'e! (")et *nsists + 1, a*ti,e -ages.

T ma/imise u! ma!"s u #u!t !*$- %e'e."nt -$%/&n and in*)ude $%%et un&t! in u! ans'e!s.

I+ u gi,e a *!!e*t nume!i*a) ans'e! 'it$ut s$'ing a)) t$e '!"ing used t (tain u! ans'e! u'i)) n) !e*ei,e u- t t' 234 ma!"s +! t$at *!!e*t nume!i*a) ans'e!.

I+ u gi,e an in*!!e*t nume!i*a) ans'e! (ut s$' sme *!!e*t '!"ing u 'i)) !e*ei,e sme ma!"s+! u! *!!e*t '!"ing.

%&te $u% "n!-e%! &n t*e te3t 4$3e! $% t"4'e e''! ("! %e5u&%ed) %$.&ded 4ene"t* e"* 5ue!t&$n6

_____________________________________________________________________________________

MAR5S S6MMAR7 TA8LE

SE9TION 9ONTENT DOMAIN MAR5S ALLO9ATED MAR5S A9HIEED

A He"t&n "nd C$$'&n 71 Ma!"s

B E'et%&"' 8und"#ent"'! ,9 Ma!"s

TOTAL MAR5S 120 Ma!"s

PER9ENTA;E MAR5

P*!&! 11: S2 EXAMINATION M6 6 MG"%% (2009) 1


2/17

Set&$n A: He"t&n "nd C$$'&n

1. W$at is t$e meaning + t$e te!m: *e"t<

3. W$at is t$e meaning + t$e te!m: &nte%n"' ene%<

#. W$at is t$e meaning + t$e te!m: te#e%"tu%e<

=> ma!"s?

In a !+@munted e."$%"t&.e "&% $$'e% 'a!m ai! +!m utside t$e $use is ()'n t$!ug$ a -adinside t$e ai! *)e! '$i*$ is satu!ated 'it$ 'ate! at !m tem-e!atu!e. T$e !esu)ting *) mist ai! t$enente!s t$e $use t$!ug$ *ei)ing ,ents.

. W$at -$si*a) %$e!! *)s t$e 'a!m ai!<

=1 ma!"?

B. H' des t$e identi+ied -!*ess *) t$e 'a!m ai!<



3/17

=3 ma!"s?>. I+ t$e -!*ess **u!!ed at a +aste! !ate 'u)d t$e amunt + *)ing (e sma))e! ! )a!ge!<

=1 ma!"?

C. W$ des an e,a-!ati,e ai! *)e! -!du*e g!eate! *)ing n a $t d! da t$an n a *) d! da<

=# ma!"s?

. W$ des an e,a-!ati,e ai! *)e! -!du*e )ess *)ing t 'a!m ai! t$at a)!ead *ntains mistu!e<

=# ma!"s?

. W$ 'u)d steam at 100 0 9 +!m t$e s-ut + an e)e*t!i* "ett)e *ause mu*$ g!eate! inu! t t$es"in n u! +inge! t$an an e%ua) mass + (i)ing 'ate! at 100 0 9 s-)as$ed nt t$e same +inge!<

T +u)) ans'e! t$is %uestin u must a--) t$ese -$si*s e%uatins: G m L and G m * T.

T$e )atent $eat + ,a-!isatin L + 'ate! is 33>0 "J "g K1. T$e s-e*i+i* + 'ate! is 1> J "g K 1 9 0 K 1.

P*!&! 11: S2 EXAMINATION M6 6 MG"%% (2009) ;


4/17

=# ma!"s?Imagine t$at u! +ami) is t!a,e))ing in a *am-e!@,an +u)) +itted ut 'it$ a gas st,e a !e+!ige!at! anda !e,e!se **)e ai! *nditine!. It is a ,e! $t da and un+!tunate) t$e ai! *nditine! $as (!"en d'n.7u! ung (!t$e! 2assuming t$at u $a,e ne4 suggests t$at $e s$u)d )ea,e t$e !e+!ige!at! d! -ent $e)- *) t$e ai! in t$e *am-e!@,an.

10. Wu)d t$is *) t$e ai! in t$e ,an ma"e n di++e!en*e ! 'a!m t$e ai! in t$e ,an m!e< 7u must

+u)) e/-)ain u! ans'e!.

=# ma!"s?

T$e $uman (d $as t$e a(i)it t !egu)ate its *!e tem-e!atu!e sme'$e!e (et'een a(ut #C 0 9 anda(ut # 0 9 '$en t$e am(ient 2su!!unding4 ai! tem-e!atu!e is (et'een a--!/imate) 30 0 9 t BB 0 9.

11. 9an u des*!i(e t' 'as ( '$i*$ t$e $uman (d !es-nds -$si)gi*a)) 2NOT (e$a,iu!a))4 t *)d su!!undings ( !edu*ing ene!g )ss< =Putting n *)t$es is nt an ans'e!.?

=3 ma!"s?

13. 9an u des*!i(e t' 'as ( '$i*$ t$e $uman (d !es-nds -$si)gi*a)) 2NOT (e$a,iu!a))4 t *)d su!!undings ( gene!ating m!e $eat ene!g< =Eating m!e is nt an ans'e!.?

P*!&! 11: S2 EXAMINATION M6 6 MG"%% (2009)


5/17

=3 ma!"s?A t'e) -)a*ed u-n $t d! sand at a (ea*$ 'i)) e,entua)) !ea*$ t$e !"#e te#e%"tu%e as t$e sand.

1#. W$ is it mu*$ m!e *m+!ta()e t stand n t$e t'e) t$an n t$e sand gi,en t$at t$e a!e at t$e!"#e te#e%"tu%e<

T$e!ma) *ndu*ti,it / + *ttn 0.0# W m K 1 9 0 K 1 and / + d! sand 0.1B K 0.3B W m K 1 9 0 K 1.

=# ma!"s?

9a!e+u)) stud t$is P$ase 9$ange ;!a-$ +! Wate! and t$en ans'e! Guestin1.

“When you heat a mixture of ice and

water, the temperature of the mixture does

not rise from 0 O C until all of the ice has

melted” 6

1. Is t$e a(,e statement t!ue<

7u must use a)) !e)e,ant s*ienti+i* *n*e-ts

2ideas4 as ne*essa! t su--!t u! 7ES ! NOans'e!.

P*!&! 11: S2 EXAMINATION M6 6 MG"%% (2009) ,


6/17

=# ma!"s?1B. W$ des 3B g + 'ate! at 10 0 9 *ntain m!e &nte%n"' ene% t$an a 30 g i*e ()*" at 0 0 9<

=3 ma!"s?

1>. W$ is it s*ienti+i*a)) &n$%%et t sa t$at 3B g + 'ate! at 10 0 9 *ntains m!e *e"t ene% t$ana 30 g i*e ()*" at 0 0 9<

=1 ma!"?

Mst -e-)e t$in" t$at t$e (est 'a t in*!ease u! !esting meta()i* !ate is t d *a!di,as*u)a!e/e!*ise )i"e !iding an e/e!*ise (i"e. A)t$ug$ t$is des $e)- a )itt)e 2it *e!tain) is (est +! u! $ea!t$ea)t$4 t$e mst e++i*ient 'a t in*!ease u! !esting meta()ism is t (ui)d u! mus*)e mass.

M! M*;a!! in*!eases $is meta()i* !ate ( 00 Watts 2J s K14 du!ing e/e!*ise n $is Re-* 8ini*

e/e!*ise (i"e. A--!/imate) CB + t$e e/t!a ene!g !e)eased is in t$e +!m + e/*ess $eat ene!g.

1C. At '$at !ate 2in "g s K14 must s'eat (e e,a-!ated t !em,e t$e e/*ess $eat ene!g -!du*ed (!iding t$e e/e!*ise (i"e< 6se t$ese t' -$si*s +!mu)ae: G m L s'eat and meta()i* !ate G tand assume a time + 1.0 se*nd.

2Latent $eat + ,a-!isatin + s'eat at a *!e@tem-e!atu!e + #C 0 9 3.B1 MJ "g K14. 2M 10 >4



7/17

= ma!"s?La' + 9nse!,atin + Ene!g !e%ui!es: Q Heat )st +!m $t (e*ts Q Heat gained ( *)d (e*ts.

1. In 8ens $use 'ate! +!m t$e $t 'ate! ta- at C0 0 9 is t $t +! a (at$. He t$e!e+!e mi/es it 'it$'ate! +!m t$e *)d 'ate! ta- at 10 0 9. W$at ,)ume + $t 'ate! s$u)d 8en add t 100.0 Lit!es +*)d 'ate! t gi,e a (at$ 'ate! tem-e!atu!e + B 0 9<

6se t$ese -$si*s +!mu)ae: G m ∆ T and Q Heat )st Q Heat gained. Nte: 7u *an *an*e) ut .

Assume t$at n) B + $eat is t!ans+e!!ed +!m t$e $t t t$e *)d 'ate! as 1B + $eat is )st +!mt$e $t 'ate! t t$e su!!undings in t$e (at$!m.

Assume t$at t$e mass + 1.00 Lit!e + $t 'ate! is t$e same as +! *)d 'ate! 1.00 "g.

= ma!"s?

Su--se t$at u a!e a $eating enginee! '$ 'ants t "n' t$e *!!e*t *a-a*it + a *ent!a) $eating

sstem t insta)) in a -a!ti*u)a! $use. 7u *an *a)*u)ate t$e $eat )sses +!m a $use using 6@,a)ues.

I+ a mate!ia) t!ans+e!s $eat 'e)) it $as a high 6@,a)ue i+ a mate!ia) is a gd insu)at! it $as a low 6@,a)ue.

Ta()e 1 gi,en (e)' s$'s t$e 6@,a)ue data +! se)e*ted *mmn $me (ui)ding mate!ia)s.

TA8LE 1: 6@AL6ES OF SELE9TED HOME 86ILDIN; MATERIALS 2W m K3

0

9 K1

4

6NINS6LATEDHO6SE

6n@insu)ated R+9ei)ing 3.0

9a,it Wa)) 1.0

Wind's single g)aed B.0

F)! 'it$ut *a!-ets 1.0

INS6LATEDHO6SE

Insu)ated R+9ei)ing 0.#

9a,it +i))ed Wa)) 0.B

Wind's double g)aed 3.B

F)! 'it$ *a!-ets 0.#

A $eating enginee! *an *a)*u)ate t$e !ate + )ss + $eat using t$e +))'ing mat$emati*a) '!d e%uatin:

Rate + Heat Lss 2Watts J s K14 6@,a)ue × A!ea × Tem-e!atu!e Di++e!en*e 2T4

P*!&! 11: S2 EXAMINATION M6 6 MG"%% (2009) =


8/17

T$e $use (eing e,a)uated +! a $eating sstem $as t$e +))'ing dimensins + a!ea as s$'n in Ta()e 3.

TA8LE 3: AREA DIMENSONS OF RELEANT PARTS OF THE HO6SE 2m 34

R+9ei)ing a!ea 100

A!ea + (!i*" 'a))s 300A!ea + 'ind's 0

F)! a!ea 100

7u must *a)*u)ate using t$e *!&! +!mu)a gi,en a(,e t$e indi,idua) !ate + $eat )ss +!m t$e !+t$e (!i*" 'a))s t$e 'ind's and t$e +)! t$en add t$em tget$e! +i!st) +! t$e un@insu)ated $use andse*nd) +! t$e insu)ated $use.

;i,en t$at t$e utside tem-e!atu!e is 0 9 and t$at t$e tem-e!atu!e inside t$e $use is t (e maintainedat 30 0 9 gi,ing a tem-e!atu!e di++e!en*e >T ? 12 0C '$at is t$e *a)*u)ated !ate + $eat )st +!m t$e:

1. 6n@insu)ated $use< =B ma!"s?

30. Insu)ated $use< =B ma!"s?

TA8LE #: TOTAL RATE OF HEAT LOST FROM THE HO6SES 2W J s K14

86ILDIN; MATERIAL 6N@INS6LATED HO6SE INS6LATED HO6SE

R+9ei)ing

8!i*" 'a))s

Wind's

F)!

T$t"' Rate + Heat Lss 2W4

31. Sme -e-)e t$in" t$at it is m!e im-!tant t insu)ate t$e 'a))s t$an t du()e@g)ae. T$is seemssensi()e as t$e 'ind's a!e sma)). Is it m!e im-!tant t insu)ate 'a))s ! t du()e@g)ae 'ind's<9mment n t$e idea gi,en a(,e !e+e!!ing t !e)e,ant ta(u)a! data and using !e)e,ant "'u'"t&$n!.

P*!&! 11: S2 EXAMINATION M6 6 MG"%% (2009) @


9/17

=# ma!"s?33. W$at is t$e di++e!en*e in t$e -ee/' *st + $eating an 6NINS6LATED $me 'it$ an INS6LATED

$me gi,en t$at t$e $eating sstem -e!ates +! n) 7 *$u%! e% d"< Time must (e in se*ndssin*e 1 Watt 1 J s K 1. 7u 'i)) need t use t$e -$si*s +!mu)a: Ene!g P'e! 2J s K14 Time 2s4.

Assume t$at t$e *st + e)e*t!i*a) ene!g 2e)e*t!i*it4 in Pe!t$ is n' a(ut .B * -e! MJ. 2M 10 >4

TA8LE : DIFFEREN9E IN HEATIN; 9OSTS

W$at is t$e *st + $eating an un&n!u'"ted $me< W$at is t$e *st + $eating an &n!u'"ted $me<

W$at is t$e 'ee") di++e!en*e in $eating *sts< 9st Di++e!en*e 2U4

=B ma!"s?

Set&$n 2: E'et%&"' 8und"#ent"'!

N' stud t$e s*$emati* diag!am gi,en (e)' + a 6nise/ ()' $ai!@d!e!.



10/17

3#. W$ is it ene% e&&ent t )*ate t$e +an mt! a+te! t$e +an and (e+!e t$e $eating *i)s<

=3 ma!"s?

T$e e)e*t!i*a) *i!*uit +! t$e $ai!@d!e! s$'n a(,e $as (een d!a'n in t$e s*$emati* diag!am (e)'.

8AN MOTOR

HEATING 2,0 ELEMENTS

E 1 E 2

S 1

S 2 S ;

T$e $eating e)ements E 1 and E 3 ea*$ d!a' B.B0 10 3 W and t$e +an mt! !e%ui!es 1B.0 W t -e!ate.

T$e ,)tage su--)ied t t$e 6nise/ ()' $ai!@d!e! is 2,0 and nt t$e usua) ,)tage + 30 .

3. W$at "d."nt"e is gained ( $a,ing t$e $eating e)ements ined in -a!a))e) and nt in se!ies<

=3 ma!"s?

T$e s'it*$ *nt!) n t$is ()' $ai!@d!e! is a!!anged s t$at S 1 must (e s'it*$ed n (e+!e S 3 and t$enS # *an (e s'it*$ed n. A)s i+ S 1 is s'it*$ed ++ t$en S 3 and S # a!e a)s s'it*$ed ++.

3B. W$ a!e t$ese s'it*$ing -!*edu!es ne*essa! +!m t$e .&e-$&nt $ !"et t t$e -e!at!<

=# ma!"s?



11/17

3>. H' mu*$ -'e! in /&'$-"tt! is used ( t$e $ai! d!e! '$en S 1 is n and S 3 and S # a!e ++<

=1 ma!"?

3C. H' mu*$ -'e! in /&'$-"tt! is used ( t$e $ai! d!e! '$en S 1 and S 3 a!e s'it*$ed n S # ++<

=1 ma!"?

3. H' mu*$ -'e! in /&'$-"tt! is used ( t$e $ai! d!e! '$en S 1 S 3 and S # a!e a)) s'it*$ed n<

=1 ma!"?

3. H' mu*$ e)e*t!i*a) ene!g in /&'$-"tt *$u%! is *nsumed ( t$e $ai! d!e! i+ it -e!ates at itsma/imum $eat setting +! B.00 minutes< 6se t$is e%uatin: Ene!g 2"W $4 P'e! 2"W4 time 2$4.

=3 ma!"s?

#0. W$at is t$e *st in *ents + d!ing u! $ai! i+ t$e d!e! -e!ates at its ma/imum $eat setting +!B.00 minutes gi,en t$at e)e*t!i*a) ene!g in Pe!t$ n' *sts a(ut 1>.01 ent! e% /&'$-"tt*$u%<

=1 ma!"?

#1. H' mu*$ *u!!ent +)'s t$!ug$ t$e "n #$t$% '$en t$e d!e! -e!ates at its ma/imum $eat setting<A--) t$e -$si*s +!mu)a: P'e! P 2W4 )tage 24 9u!!ent I 2A4.

=3 ma!"s?



12/17

#3. H' mu*$ *u!!ent +)'s t$!ug$ t$e *e"t&n e'e#ent E 1 '$en t$e d!e! -e!ates at its ma/imum$eat setting< A--) t$e -$si*s +!mu)a: P'e! P 2W4 )tage 24 9u!!ent I 2A4.

=3 ma!"s?

##. H' mu*$ *u!!ent +)'s t$!ug$ t$e *e"t&n e'e#ent E 3 '$en t$e d!e! -e!ates at its ma/imum$eat setting< A--) t$e -$si*s +!mu)a: P'e! P 2W4 )tage 24 9u!!ent I 2A4.

=3 ma!"s?

W$en u tu!n t$e "e in a *a! ignitin a num(e! + e)e*t!i*a) *i!*uits ma (e a*ti,ated. T$e ne sstemt$!ug$ '$i*$ mst *u!!ent 'i)) +)' is + *u!se t$e sta!te!@mt!. T$e *i!*uit d!a'n (e)' s$'s in a,e! sim-)i+ied 'a $' t$e sta!te!@mt! is *nne*ted t t$e *a! (atte!. T$e !e%ui!ed s'it*$es $a,e

(een mitted t ma"e t$e diag!am sim-)e!.

T$e *a! e)e*t!i*a) sstem is using a ne"t&.e e"%t* %etu%n i.e. t$e negati,e te!mina) + t$e *a! (atte! is*nne*ted t t$e meta) (d + t$e *a!.

T*&/ $nnet&n "4'e!

12 STARTER

C"% B"tte% MOTOR

10

E"%t*ed t$ C"%B$d

W$en u sta!t a *)d engine t$e *u!!ent +)'ing +!m a 12 *a! (atte! *an !ea*$ a ma/imum 100 Aand t$e ,)tage a*!ss t$e sta!te! mt! must (e e%ua) t ! g!eate! t$an 10 .

#. A**!ding t &%**$D! !e$nd L"- '$at ,)tage 'u)d e/ist a)ng t$e t$i*" *nne*ting *a()es<

=3 ma!"s?



13/17

#B. W$at is t$e #"3u# !esistan*e + t$e t$i*" *nne*ting *a()es< A--) O$ms La': I R.

=3 ma!"s?

#>. ;i,en t$at t$e t$i*" *nne*ting *a()es a!e made + *--e! + %e!&!t&.&t 1. 10 K Ω m and t$at

t$ei! tta) )engt$ F is 1.B m '$at minimum *a()e *!ss@se*tina) a!ea A must (e used s as t -!e,entan ,e!@$eating + t$e *a()es< A--) t$is -$si*s +!mu)a: R 2V 4 A.

=# ma!"s?

In 9i!*uit A t$e t' identi*a) g)(es a!e in se!ies. In 9i!*uit 8 t$e same t' g)(es a!e in -a!a))e).

T$e (atte! in 9i!*uit A and t$e (atte! in 9i!*uit 8 a!e identi*a) and t$e su--) t$e same ,)tage 2 4.

#C. W$at te + e)e*t!i* *u!!ent is s$'n in t$e a(,e t' *i!*uit diag!ams< 7u must !e+e! t t$e -)a!it + t$e (atte! te!mina)s and t t$e s*ienti+i* +a*t t$at: 6n)i"e e)e*t!i* *$a!ges att!a*t '$e!eas)i"e e)e*t!i* *$a!ges !e-e) t e/-)ain u! ans'e!. Is t$e *u!!ent *n,entina) ! is it e)e*t!n +)'<

=# ma!"s?

P*!&! 11: S2 EXAMINATION M6 6 MG"%% (2009) 1;

T O R 9 H ; L O 8 E S I N S E R I E S A N D I N P A R A L L E L

: :

R R

R

R

C I R C U I T A C I R C U I T B

G L O B E A 1 G L O B E A 2

I I


14/17

H-t$eti*a) *n,entina) *u!!ent in a *--e! 'i!e *nne*ted a*!ss a (atte! is a +)' + -siti,e*$a!ges a!und t$e e)e*t!i* *i!*uit +!m t$e -siti,e 24 te!mina) t negati,e 2 4 te!mina) + t$e (atte!.

#. T$e -siti,e *$a!ges )*ated inside a *--e! 'i!e *annt +)' as *n,entina) *u!!ent a!und ane)e*t!i* *i!*uit ,ia t$e *--e! 'i!es. W$ *ant t$e -siti,e *$a!ges +)' t$!ug$ t$e *--e! 'i!e<

=# ma!"s?

T$e (!ig$tness + an !dina! in*andes*ent e)e*t!i* )ig$t g)(e de-ends n t$e tem-e!atu!e + its +i)ament.

T$e tem-e!atu!e + t$e g)(e +i)ament de-ends n ,)tage a--)ied a*!ss it and *u!!ent +)'ing t$!ug$ it.

T$e (!ig$tness + a g)(e is dete!mined ( t$e ,)tage a--)ied a*!ss it and t$e *u!!ent +)'ing t$!ug$ it.

#. W$ des t$e tem-e!atu!e + t$e +i)ament + a )ig$t g)(e de-end n t$e a--)ied ,)tage<

=# ma!"s?

0. W$ des t$e tem-e!atu!e + t$e +i)ament + a )ig$t g)(e de-end n t$e *u!!ent +)'ing t$!ug$ it<

=# ma!"s?

1. A!e t$e t' g)(es s$'n in C&%u&t A e%ua)) (!ig$t i+ t$e a!ent '$i*$ ne is (!ig$te! and '$<

=3 ma!"s?



15/17

3. W$at ,)tage is a--)ied a*!ss ea*$ g)(e in C&%u&t B<

=1 ma!"?

#. W$at ,)tage is a--)ied a*!ss ea*$ g)(e in C&%u&t A<

=1 ma!"?

. W$at is t$e !ati + t$e ,)tages a--)ied a*!ss ea*$ g)(e in C&%u&t B t t$at in C&%u&t A<

=3 ma!"s?

B. W$at is t$e tta) !esistan*e + C&%u&t A< 6se t$is -$si*s +!mu)a: R SERIES R 1 R 3

=1 ma!"?

>. H' mu*$ *u!!ent +)'s t$!ug$ ea*$ g)(e in C&%u&t A< A--) O$ms La': I R.

=3 ma!"s?

C. W$at is t$e tta) !esistan*e + C&%u&t B< 6se t$is -$si*s +!mu)a: R PARALLEL 21R 1 1R 3 4 K1.

=1 ma!"?

P*!&! 11: S2 EXAMINATION M6 6 MG"%% (2009) 1,


16/17

. H' mu*$ *u!!ent +)'s t$!ug$ ea*$ g)(e in C&%u&t B< A--) O$ms La': I R.

=3 ma!"s?

. W$at is t$e !ati + t$e *u!!ents +)'ing t$!ug$ ea*$ g)(e in C&%u&t B t t$at in C&%u&t A<

=3 ma!"s?

B0. W$at e)e*t!i*a) -'e! is d!a'n (e ea*$ g)(e in C&%u&t B< 6se: P'e! P )tage × 9u!!ent I.

=3 ma!"s?

B1. W$at e)e*t!i*a) -'e! is d!a'n (e ea*$ g)(e in C&%u&t A< 6se: P'e! P )tage × 9u!!ent I.

=3 ma!"s?

B3. W$at is t$e !ati + t$e -'e! d!a'n ( ea*$ g)(e in C&%u&t B t t$at in C&%u&t A<

=3 ma!"s?

B#. In te!ms + t$e e)e*t!i*a) -'e! d!a'n ( ea*$ g)(e *$- #"n te! 4%&*te% a!e t$e g)(es inC&%u&t B *m-a!ed t t$e g)(es in C&%u&t A<



17/17

=1 ma!"?

S*$u'd $u *".e d&&u't &n !$'.&n ue!t&$n!

s.4 phys ex q (singa)

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