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CBSE Class 10 Board Exam 2020 : Science (Series 4)

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Kendriya Vidyalaya (KV), Kamla Nehru Nagar, Ghaziabad

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H$moS> Z . Code No. amob Z . 31/4/1 narjmWu H$moS >H$mo C ma-nwp VH$m Ho$ _wI-n >na Ad ` {bIo & Roll No. Candidates must write the Code on the title page of the answer-book. (I) ZmoQ> H $n`m Om M H$a b| {H$ Bg Z-n _o _w{ V n > 23 h & (II) Z-n _| Xm{hZo hmW H$s Amoa {XE JE H$moS >Z ~a H$mo N>m C ma-nwp VH$m Ho$ _wI-n > na {bI| & (III) H $n`m Om M H$a b| {H$ Bg Z-n _| >30 Z h & H $n`m Z H$m C ma {bIZm ew $ H$aZo go nhbo, C ma-nwp VH$m _| Z H$m H $_m H$ Ad ` {bI| & Bg Z-n H$mo n T>Zo Ho$ {bE 15 {_ZQ >H$m g_` {X`m J`m h & Z-n H$m {dVaU nydm _| 10.15 ~Oo {H$`m OmEJm & 10.15 ~Oo go 10.30 ~Oo VH$ N>m Ho$db Z-n H$mo n T>|Jo Am a Bg Ad{Y Ho$ Xm amZ do C ma-nwp VH$m na H$moB C ma Zht {bI|Jo & (IV) (V) NOTE (I) Please check that this question paper contains 23 printed pages. (II) Code number given on the right hand side of the question paper should be written on the title page of the answer-book by the candidate. (III) Please check that this question paper contains 30 questions. (IV) Please write down the serial number of the question in the answer-book before attempting it. (V) 15 minute time has been allotted to read this question paper. The question paper will be distributed at 10.15 a.m. From 10.15 a.m. to 10.30 a.m., the students will read the question paper only and will not write any answer on the answer-book during this period. {dkmZ SCIENCE {ZYm [aV g_` : 3 K Q>o A{YH$V_ A H$ : 80 Time allowed : 3 hours .31/4/1 Maximum Marks : 80 1 P.T.O. gm_m ` {ZX}e : {Z Z{b{IV {ZX}em| H$mo ~h V gmdYmZr go n{ T>E Am a CZH$m g Vr go nmbZ H$s{OE : (i) `h Z-n VrZ I S>m| _ o {d^m{OV {H$`m J m h H$, I Am a J & Bg Z-n _| Zm| H$s g `m 30 h & g^r Z A{Zdm` h & (ii) I S> H$ Ho$ g^r Z/CZHo$ ^mJ, Z g `m 1 go 14 VH$ EH$-EH$ A H$ Ho$ h & BZ Zm| _| ~h {dH$ nr Z, A{V bKw-C mar` Z VWm A{^H$WZ-H$maU H$ma Ho$ Zm| H$mo gp _{bV {H$`m J`m h & BZ Zm| Ho$ C ma EH$ e X AWdm EH$ dm ` _| {XE OmZo Mm{hE & (iii) I S> I _| Z g `m 15 go 24 VH$ bKw-C mar` H$ma Ho$ Z h , `oH$ Z 3 A H$ H$m h & BZ Zm| H$m C ma 50 go 60 e Xm| go A{YH$ Zht hmoZm Mm{hE & (iv) I S> J _| Z g `m 25 go 30 VH$ XrK -C mar` H$ma Ho$ Z h , `oH$ Z 5 A H$ H$m h & BZ Zm| H$m C ma 80 go 90 e Xm| go A{YH$ Zht hmoZm Mm{hE & (v) C ma g {j VWm q~X dma hmoZo Mm{hE Am a gmW hr Cn`w $ e X gr_m H$m `Wmg ^d nmbZ {H$`m OmZm Mm{hE & (vi) Z-n _| g_J na H$moB {dH$ n Zht h & VWm{n `oH$ I S> _| Hw$N> Zm| _| Am V[aH$ {dH$ n {XE JE h & Eogo Zm| _ o go Ho$db EH$ hr {dH$ n H$m C ma {b{IE & (vii) BgHo$ A{V[a $, Amd `H$VmZwgma, `oH$ I S> Am a Z Ho$ gmW `Wmo{MV {ZX}e {XE JE h & I S> H$ 147 N _| Cnp WV g `moOr Bbo Q >m Zm| H$s g `m {b{IE & 1. ZmBQ >moOZ na_mUw 2. o[aV {d wV Ymam H$s n[a^mfm {b{IE & 3. {Z Z{b{IV AZw N>oX Am a n T>r J`t g ~ {YV g H$ nZmAm| H$s `m `m Ho$ AmYma na Z g `m 3(a) go 3(d) Ho$ C ma Xr{OE : 1 gZ 1800 Ho$ bJ^J VH$ Ho$db 30 V d hr kmV Wo & 1817 _| S>m ~oamBZa Am a 1866 _| `yb S >g Zo V~ VH$ kmV V dm| H$mo `dp WV H$aZo Ho$ {bE `mg {H$E Am a Hw$N> {Z`_ ~ZmE {O h| d km{ZH$m| Zo A drH$ma H$a {X`m & CZ Vm{dV {Z`_m| Ho$ A drH$ma {H$E OmZo Ho$ n MmV ^r H$B d km{ZH$m| Zo Eogo {V $nm| H$s ImoO Omar aIr {Oggo V dm| Ho$ JwUY_m] H$m CZHo$ na_mUw `_mZm| Ho$ gmW g ~ Y Wm{nV hmo gHo$ & .31/4/1 1 2 General Instructions : Read the following instructions very carefully and strictly follow them. (i) This question paper comprises three Sections A, B and C. There are 30 questions in the question paper. All questions are compulsory. (ii) Section A Questions no. 1 to 14 all questions or part thereof are of one mark each. These questions comprise Multiple Choice Questions (MCQ), Very Short Answer (VSA) and Assertion Reason type questions. Answer to these questions should be given in one word or one sentence. (iii) Section B Questions no. 15 to 24 are short answer type questions, carrying 3 marks each. Answer to these questions should not exceed 50 to 60 words. (iv) Section C Questions no. 25 to 30 are long answer type questions, carrying 5 marks each. Answer to these questions should not exceed 80 to 90 words. (v) Answers should be brief and to the point. Also the above mentioned word limit be adhered to as far as possible. (vi) There is no overall choice in the question paper. However, an internal choice has been provided in some questions in each section. Only one of the choices in such questions have to be attempted. (vii) In addition to this, separate instructions are given with each section and question, wherever necessary. SECTION A 1. Write the number of valence electrons present in a nitrogen atom 2. Define the term induced electric current. 3. Answer question numbers 3(a) 3(d) on the basis of your understanding of the following paragraph and the related studied concepts : 147 N . 1 1 Around the year 1800, only 30 elements were known. Dobereiner in 1817 and Newlands in 1866 tried to arrange the then known elements and framed laws which were rejected by the scientists. Even after the rejection of the proposed laws, many scientists continued to search for a pattern that correlated the properties of elements with their atomic masses. .31/4/1 3 P.T.O. V dm| Ho$ dJuH$aU H$m _w ` lo` _o S>obr\$ H$mo OmVm h , {O hm|Zo V dm| H$s AmdV gmaUr Ho$ ma {^H$ {dH$mg _| gdm {YH$ _h dnyU `moJXmZ {X`m & C hm|Zo V dm| H$mo CZHo$ _yb JwUY_ , na_mUw `_mZ VWm amgm`{ZH$ JwUY_m] _| g_mZVm Ho$ AmYma na `dp WV {H$`m & CZHo$ hmBS >mBS>m| Am a Am gmBS>m| Ho$ gy m| H$mo V dm| Ho$ dJuH$aU H$m _yb _mnX S> _mZm J`m & na Vw _o S>obr\$ Ho$ dJuH$aU _| ^r Hw$N> H${_`m Wt, `m|{H$ Bg_| g_ Wm{ZH$m| H$mo H$moB WmZ Zht {X`m J`m Wm & C hm|Zo AmdV gmaUr _| Hw$N> [a $ WmZ ^r N>mo S> {XE Wo & 3(a) _o S>obr\$ H$m AmdV {Z`_ {b{IE & 3(b) _o S>obr\$ Zo AmdV gmaUr _| Hw$N> [a $ WmZ `m| N>mo S> {XE Wo 3(c) `{X {H$gr g_yh _| {H$gr V d H$mo R Aja go {Z ${nV {H$`m OmVm h , Vmo H$m~ Z Ho$ hmBS >mBS> Am a Am gmBS> H$mo H $_e: {H$g H$ma {Z ${nV {H$`m OmEJm ? 3(d) .31/4/1 (i) RH4, RO (ii) RH4, RO2 (iii) RH2, RO2 (iv) RH2, RO 1 ? 1 1 1 g_ Wm{ZH$ (i) {H$gr V d Ho$ dh na_mUw h {OZHo$ amgm`{ZH$ JwUY_ g_mZ na Vw na_mUw `_mZ {^ hmoVo h & (ii) {^ -{^ V dm| Ho$ dh na_mUw h {OZHo$ amgm`{ZH$ JwUY_ g_mZ na Vw na_mUw `_mZ {^ hmoVo h & (iii) {H$gr V d Ho$ dh na_mUw h {OZHo$ amgm`{ZH$ JwUY_ {^ na Vw na_mUw `_mZ g_mZ hmoVo h & (iv) {^ -{^ V dm| Ho$ dh na_mUw h {OZHo$ amgm`{ZH$ JwUY_ {^ na Vw na_mUw `_mZ g_mZ hmoVo h & 4 The main credit for classifying elements goes to Mendeleev for his most important contribution to the early development of a Periodic table of elements wherein he arranged the elements on the basis of their fundamental property, the atomic mass and also on the similarity of chemical properties. The formulae of their hydrides and oxides were treated as basic criteria for the classification of the elements. However, Mendeleev s classification also had some limitations as it could not assign the position to isotopes. He also left some gaps in the periodic table. 3(a) State Mendeleev s Periodic Law. 1 3(b) Why did Mendeleev leave some gaps in the Periodic table ? 1 3(c) If the letter R was used to represent any of the elements in the group, then the hydride and oxide of carbon would respectively be represented as 1 3(d) (i) RH4, RO (ii) RH4, RO2 (iii) RH2, RO2 (iv) RH2, RO Isotopes are 1 (i) Atoms of an element with similar chemical properties but different atomic masses. (ii) Atoms of different elements with similar chemical properties but different atomic masses. (iii) Atoms of an element with different chemical properties but same atomic masses. (iv) Atoms of different elements with different chemical properties but same atomic masses. .31/4/1 5 P.T.O. 4. {Z Z{b{IV AZw N>oX Am a n T>r J`t g ~ {YV g H$ nZmAm| H$s `m `m Ho$ AmYma na Z g `m 4(a) go 4(d) Ho$ C ma Xr{OE : ^maV AmO g gmYZm| Ho$ A `{YH$ XmohZ, Ob Am a _ Xm Ho$ g X fU VWm H$Mao H$mo g gm{YV H$aZo H$s {d{Y`m| H$s H$_r H$s g_ `m H$m gm_Zm H$a ahm h & A~ g_` Am J`m h {H$ g gma EH$b-Cn`moJ bmp Q>H$ H$mo {dXm H$ho & BgHo$ n`m daU-{hV fr {dH$ nm|, An{e Q> bmp Q>H$ H$m ^mdr EH$ rH$aU Am a CgH$m {ZnQ>mam H$aZo H$s {d{Y`m {dH${gV H$aZo Ho$ {bE `mg {H$E OmZo Mm{hE & B Xm a Zo _m 3 df _| O d-IZZ Am a O d-CnMm` H$s {H $`mAm| mam 15 bmI _r{Q >H$ Q>Z H$Mao H$mo g gm{YV {H$`m h & O d-CnMm` _| {H$gr b S>{\$b _| OrdmUwAm| H$mo S>mbH$a H$Mao H$mo mH ${VH$ $n go AnK{Q>V {H$`m OmVm h VWm O d-IZZ _| Q >mo_b _erZm| mam H$Mao H$mo N>mZH$a _ Xm H$mo H$Mao go n WH $ {H$`m OmVm h & Bg eha Zo bJ^J 10 H$amo S> n`o IM H$aHo$ 15 bmI _r{Q >H$ Q>Z H$Mao H$m {ZnQ>mam H$aZo _| g\$bVm nmB & Eogm hr EH$ g\$b `moJ Ah_Xm~mX _| ^r {H$`m J`m & 4(a) AnZo {d mb` _| An{e Q> bmp Q>H$ H$mo EH$ H$aZo H$s Xmo ^mdr {d{Y`m| H$m C boI H$s{OE & 1 4(b) EH$b-Cn`moJ bmp Q>H$ Ho$ X {ZH$ OrdZ _| H$moB Xmo Cn`moJ {b{IE & 1 4(c) `{X bmp Q>H$ H$m Cn`moJ amoH$ {X`m OmE, Vmo BgHo$ WmZ na H$moB n`m daU-{hV fr {dH$ n H $go XmZ {H$`m Om gH$Vm h ? 4(d) `m Amn Eogm gmoMVo h {H$ b S>{\$b Wb _| OrdmUw Cgr H$ma H$m` H$a|Jo O gm do `moJembm _| H$aVo h ? AnZo C ma H$s nw{ Q> H$s{OE & .31/4/1 1 6 1 4. Answer question numbers 4(a) 4(d) on the basis of your understanding of the following paragraph and the related studied concepts : India today is facing the problem of overuse of resources, contamination of water and soil and lack of methods of processing the waste. The time has come for the world to say goodbye to single-use plastics . Steps must be undertaken to develop environment-friendly substitutes, effective plastic waste collection and methods of its disposal. Indore treated 15 lakh metric tonnes of waste in just 3 years, through biomining and bioremediation techniques. Bioremediation involves introducing microbes into a landfill to naturally break it down and biomining involves using trommel machines to sift through the waste to separate the soil and the waste component. The city managed to chip away 15 lakh metric tonnes of waste at a cost of around < 10 crore. A similar experiment was successfully carried out in Ahmedabad also. 4(a) State two methods of effective plastic waste collection in your school. 1 4(b) Name any two uses of single-use plastic in daily life. 1 4(c) If we discontinue the use of plastic, how can an environment-friendly substitute be provided ? 4(d) Do you think microbes will work similarly in landfill sites as they work in the laboratory ? Justify your answer. .31/4/1 1 7 1 P.T.O. 5. 6. _mZd n[ag MaU V Ho$ {df` _| {Z Z{b{IV _| go H$m Z-gm H$WZ ghr h ? (A) {Ya Ho$db Am grOZ H$m dhZ H$aVm h VWm H$m~ Z S>mBAm gmBS> H$m dhZ Zht H$aVm & (B) _mZd X` _| nm M H$mo R> hmoVo h & (C) dm d {Ya Ho$ n M dmh na amoH$ H$mo gw{Zp MV H$aVo h & (D) X` _| Am grOZ-~h b Am a Am grOZ- `yZ XmoZm| {Ya {_{lV hmoVo h & 1 1 Adm`dr` {H $`m (A) {H$ dZ Ho$ g_` `r Q> _| hmoVr h & (B) Am grOZ H$s Cnp W{V _| hmoVr h & (C) _mZdm| H$s no{e`m| _| Ho$db D$Om C n H$aVr h & (D) _| EWoZm b, Am grOZ Am a D$Om C n hmoVr h & AWdm ^moOZ H$m A{YH$m e nmMZ Am a AdemofU H$hm hmoVm h 7. (A) jw m _| (B) `H $V _| (C) Am_me` _| (D) ~ h m _| ? 1 {ZfoMZ dh {H $`m h {Og_| (A) Za `w _H$ H$m _mXm `w _H$ H$s Amoa WmZm VaU hmoVm h & (B) Za Am a _mXm `w _H$ Ho$ Ho$ H$m| H$m g b`Z hmoVm h & (C) Za Am a _mXm OZZm Jm| H$m Amg OZ ({MnH$md) hmoVm h & (D) {H$gr OZZm J mam `w _H$ ~ZVo h & .31/4/1 1 8 5. Which one of the following statements is correct about the human circulatory system ? 1 (A) Blood transports only oxygen and not carbon dioxide. (B) Human heart has five chambers. (C) Valves ensure that the blood does not flow backwards. (D) Both oxygen-rich and oxygen-deficient blood gets mixed in the heart. 6. Anaerobic process 1 (A) takes place in yeast during fermentation. (B) takes place in the presence of oxygen. (C) produces only energy in the muscles of human beings. (D) produces ethanol, oxygen and energy. OR Most of the digestion and absorption of the food takes place in the 7. (A) small intestine. (B) liver. (C) stomach. (D) large intestine. Fertilisation is the process of 1 (A) transfer of male gamete to female gamete. (B) fusion of nuclei of male and female gamete. (C) adhesion of male and female reproductive organs. (D) the formation of gametes by a reproductive organ. .31/4/1 1 9 P.T.O. 8. `{X {H$gr `{ $ Ho$ nmg nm M {VamoYH$ h {OZ_| `oH$ H$m {VamoY g `mo{OV H$aHo$ {H$VZm A{YH$V_ {VamoY m V H$a gH$Vm h (A) 1 (B) 5 (C) 10 (D) 25 1 5 h , Vmo dh B h| ? 1 AWdm {H$gr {VamoYH$ H$m {VamoY CgHo$ map ^H$ _mZ H$m AmYm H$a {X`m J`m h & Eogm H$aZo _|, `{X n[anW Ho$ A ` mMbm| H$mo n[ad{V V Z {H$`m OmE, Vmo Bg {VamoYH$ _| VmnZ 1 ^md hmo OmEJm 9. (A) X JwZm (B) AmYm (C) EH$-Mm WmB (D) Mma JwZm boq_J H$m X{jU-h V {Z`_ ~VmVm h 1 (A) o[aV Ymam H$m n[a_mU & (B) Mw ~H$s` jo H$m n[a_mU & (C) o[aV Ymam H$s {Xem & (D) o[aV Ymam H$s {Xem Am a n[a_mU, XmoZm| & .31/4/1 10 8. If a person has five resistors each of value resistance he can obtain by connecting them is (A) 1 (B) 5 (C) 10 (D) 25 1 , then the maximum 5 1 OR The resistance of a resistor is reduced to half of its initial value. In doing so, if other parameters of the circuit remain unchanged, the heating effects in the resistor will become 9. (A) two times. (B) half. (C) one-fourth. (D) four times. 1 Fleming s Right-hand rule gives 1 (A) magnitude of the induced current. (B) magnitude of the magnetic field. (C) direction of the induced current. (D) both, direction and magnitude of the induced current. .31/4/1 11 P.T.O. 10. {H$gr Zm{^H$s` [aEo Q>a _| Zm{^H$s` D$Om C n H$aZo Ho$ ~mao _| {Z Z{b{IV _| go H$m Z-gm H$WZ g ` Zht h ? (A) Bg_| D$Om Zm{^H$s` {dI S>Z H$s {H $`m mam m V hmoVr h & (B) Bg_| `yao{Z`_ Ho$ Zm{^H$ na C M D$Om dmbo `yQ >m Zm| H$s ~_~mar H$s OmVr h & (C) Bg {H $`m _| m Ibm A{^{H $`m hmoVr h & (D) Bg {H $`m _| {Z` { V Xa na {demb _m m _| D$Om _w $ hmoVr h & 1 AWdm n dr Ho$ n R> na D$Om H$m g~go ~ S>m moV h 11. 12. (A) O d_m m (~m`mo_mg) (B) gm a {d{H$aU (C) dma-^mQ>m (D) ndZ Amhma Omb ~ZVm h (A) Ordm| Am a n`m daU Ho$ ~rM g ~ Y mam (B) nmXnm| Am a O VwAm| Ho$ ~rM g ~ Y mam (C) {H$gr nm[aV _| {d{^ Amhma m IbmAm| Ho$ Omo S> go (D) O VwAm| Am a n`m daU Ho$ ~rM g ~ Y mam {Z Z{b{IV _| go Ag ` H$WZ Mw{ZE : 1 1 (A) Am grOZ Ho$ VrZ na_mUwAm| go Amo OmoZ H$m EH$ AUw ~ZVm h & (B) Amo OmoZ nam~ JZr {d{H$aUm| go n dr Ho$ n R> H$s gwajm H$aVr h & (C) Amo OmoZ A ` V {df br hmoVr h & (D) Amo OmoZ nam~ JZr {d{H$aUm| mam AnK{Q>V ({d`mo{OV) hmo OmVr h & .31/4/1 1 12 10. Which one of the following statements is not true about nuclear energy generation in a nuclear reactor ? (A) Energy is obtained by a process called nuclear fission. (B) The nucleus of Uranium is bombarded with high energy neutrons. (C) A chain reaction is set in the process. (D) In this process a tremendous amount of energy is released at a controlled rate. 1 OR The biggest source of energy on Earth s surface is 11. 12. (A) Biomass (B) Solar radiations (C) Tides (D) Winds 1 Food web is constituted by 1 (A) relationship between the organisms and the environment. (B) relationship between plants and animals. (C) various interlinked food chains in an ecosystem. (D) relationship between animals and environment. Choose the incorrect statement from the following : 1 (A) Ozone is a molecule formed by three atoms of oxygen. (B) Ozone shields the surface of the Earth from ultraviolet radiations. (C) Ozone is deadly poisonous. (D) Ozone gets decomposed by UV radiations. .31/4/1 13 P.T.O. Z g `m 13 Am a 14 Ho$ {bE, Xmo H$WZ {XE JE h {OZ_| EH$ H$mo A{^H$WZ (A) VWm X gao H$mo H$maU (R) mam A {H$V {H$`m J`m h & BZ Zm| Ho$ ghr C ma ZrMo {XE JE H$moS>m| (a), (b), (c) Am a (d) _| go MwZH$a Xr{OE & (a) (b) (c) (d) 13. (A) Am a (R) XmoZm| ghr h Am a (R), A{^H$WZ (A) H$s ghr `m `m H$aVm h & (A) Am a (R) XmoZm| ghr h , na Vw (R), A{^H$WZ (A) H$s ghr `m `m Zht H$aVm h & (A) ghr h , na Vw (R) JbV h & (A) JbV h , na Vw (R) ghr h & A{^H$WZ (A) : {Z Z{b{IV g Vw{bV amgm`{ZH$ g_rH$aU Am`aZ na ^mn H$s {H $`m Ho$ {bE h : 3Fe + 4H2O Fe3O4 + 4H2 H$maU (R) : 14. {H$gr amgm`{ZH$ g_rH$aU na `_mZ Ho$ g ajU H$m {Z`_ bmJy hmoVm h & 1 A{^H$WZ (A) : _mZdm| _| {H$gr {eew H$m qbJ CgHo$ {nVm mam d emZwJV JwUgy Ho$ H$ma mam {ZYm [aV hmoVm h & H$maU (R) : 15. dh {eew Omo AnZo {nVm go X JwUgy d emZwJV H$aVm h b S>H$s (XX) hmoVr h O~{H$ dh {eew Omo AnZo {nVm go Y JwUgy d emZwJV H$aVm h b S>H$m (XY) hmoVm h & 1 I S> I H$moB naIZbr, {Og_| nmoQ> {e`_ Am`moS>mBS> H$m {db`Z ^am h , _| b S> ZmBQ >oQ> {db`Z {_bm`m J`m h & (a) Adjo{nV `m {JH$ H$m Zm_ Am a a J {b{IE & (b) hmoZo dmbr A{^{H $`m H$m g Vw{bV amgm`{ZH$ g_rH$aU {b{IE & (c) Bg A{^{H $`m Ho$ H$ma H$m Zm_ {b{IE Am a AnZo C ma H$s nw{ Q> H$s{OE & AWdm `m hmoVm h O~ dgm VWm V br` Im gm_J r b ~o g_` VH$ aIr ah OmVr h ? ojU `mo ` Xmo n[adV Zm| H$s gyMr ~ZmBE Am a Bg n[aKQ>Zm go ~Mmd Ho$ VrZ Cnm` gwPmBE & .31/4/1 14 3 3 For question numbers 13 and 14, two statements are given one labelled as Assertion (A) and the other labelled as Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below : 13. (a) Both (A) and (R) are true and (R) is the correct explanation of the assertion (A). (b) Both (A) and (R) are true, but (R) is not the correct explanation of the assertion (A). (c) (A) is true, but (R) is false. (d) (A) is false, but (R) is true. Assertion (A) : Following is a balanced chemical equation for the action of steam on iron : 3Fe + 4H2O Fe3O4 + 4H2 Reason (R) : 14. The law of conservation of mass holds good for a chemical equation. 1 Assertion (A) : The sex of a child in human beings will be determined by the type of chromosome he/she inherits from the father. Reason (R) : A child who inherits X chromosome from his father would be a girl (XX), while a child who inherits a Y chromosome from the father would be a boy (XY). 1 SECTION B 15. Lead nitrate solution is added to a test tube containing potassium iodide solution. (a) Write the name and colour of the compound precipitated. (b) Write the balanced chemical equation for the reaction involved. (c) Name the type of this reaction justifying your answer. 3 OR What happens when food materials containing fats and oils are left for a long time ? List two observable changes and suggest three ways by which this phenomenon can be prevented. .31/4/1 15 3 P.T.O. 16. 17. 18. 19. 20. 21. `eXbonZ VWm {_lm dZ H$s {H $`mAm| Ho$ ~rM VrZ {d^oXZH$mar bjUm| H$s gyMr ~ZmBE & AWdm Vm{bH$m Ho$ $n _| {Z Z{b{IV YmVwAm| H$s R> S>o Am a J_ Ob Ho$ gmW A{^{H $`merbVmAm| H$s VwbZm H$s{OE : (a) gmo{S>`_ (b) H $p g`_ (c) _ Zr{e`_ H$m~ Z, Omo {H$ g_yh 14 H$m gX ` h , A `{YH$ g `m _| H$m~ Z `m {JH$m| H$m {Z_m U H$aVm h {OZH$s AZw_m{ZV g `m bJ^J 30 bmI h & Bgr JwwUY_ H$mo Bgr g_yh Ho$ A ` V d X{e V `m| Zht H$aVo h ? `m `m H$s{OE & H$moB MrVm, AnZo {eH$ma H$mo XoIH$a, CgH$s Amoa A `{YH$ Vrd J{V go Xm S>Vm h & CgH$s no{e`m| H$mo {H$g H$ma J{V {_bVr h ? Bg n[aKQ>Zm Ho$ g_` no{e`m| Ho$ H$mo{eH$s` Ad`dm| Ho$ agm`Z _| `m n[adV Z hmoVm h ? Jw dmZwdV Z H$s n[a^mfm {b{IE & {H$gr nmXn Ho$ ^mJm| _| Jw dmZwdVu J{V`m| H$mo Xem Zo Ho$ {bE Zm_m {H$V AmaoI It{ME & {dH$mg H$s n[a^mfm {b{IE & {dH$mg H$mo J{V Ho$ g_mZ Zht _mZm Om gH$Vm h & Bg H$WZ H$s nw{ Q> H$s{OE & AWdm {dH$mg H$s {H $`m H$s Ad{Y _|, A J AWdm bjU ZE H$m`m] Ho$ {bE AZwHy${bV hmo gH$Vo h & H$moB Cn`w $ CXmhaU XoH$a Bg V ` H$s `m `m H$s{OE & {H$gr AdVb Xn U H$m Cn`moJ {H$gr {~ ~ H$s {d{^ p W{V`m| _| CgH$m {V{~ ~ ~ZmZo Ho$ {bE {H$`m J`m h & O~ `h {~ ~ 15 cm \$moH$g X ar Ho$ AdVb Xn U Ho$ Y wd go 10 cm X ar na aIm h , Vmo Bg p W{V _| {Z Z{b{IV Ho$ {df` _| `m {Z H$f {ZH$mbo Om gH$Vo h ? (a) {V{~ ~ H$s p W{V (b) {V{~ ~ H$m gmB O (c) {V{~ ~ H$s H ${V AnZo {Z H$fm] H$s nw{ Q> Ho$ {bE Zm_m {H$V {H$aU AmaoI It{ME & .31/4/1 16 3 3 3 3 3 3 3 3 16. List three differentiating features between the processes of galvanisation and alloying. 3 OR Compare in tabular form the reactivities of the following metals with cold and hot water : 17. 18. 19. 20. (a) Sodium (b) Calcium (c) Magnesium 3 Carbon, a member of group 14, forms a large number of carbon compounds estimated to be about three million. Why is this property not exhibited by other elements of this group ? Explain. 3 A cheetah, on seeing a prey, moves towards him at a very high speed. What causes the movement of his muscles ? How does the chemistry of cellular components of muscles change during this event ? 3 Define geotropism. Draw a labelled diagram of a plant showing geotropic movements of its parts. 3 Define the term evolution. Evolution cannot be equated with progress. Justify this statement. 3 OR During the course of evolution, organs or features may be adapted for new functions. Explain this fact by choosing an appropriate example. 21. 3 A concave mirror is used for image formation for different positions of an object. What inferences can be drawn about the following when an object is placed at a distance of 10 cm from the pole of a concave mirror of focal length 15 cm ? (a) Position of the image (b) Size of the image (c) Nature of the image Draw a labelled ray diagram to justify your inferences. .31/4/1 17 3 P.T.O. 22. 23. 24. _m `_ x H$m _m `_ y Ho$ gmnoj AndV Zm H$ 2/3 h VWm _m `_ y H$m _m `_ z Ho$ gmnoj AndV Zm H$ 4/3 h & _m `_ x Ho$ gmnoj _m `_ z H$m AndV Zm H$ kmV H$s{OE & `{X _m `_ x _| H$me H$s Mmb 3 108 ms 1 h , Vmo _m `_ y _| H$me H$s Mmb n[aH${bV H$s{OE & 3 H$moB `{ $ {ZH$Q>- { Q>> Xmof VWm XrK - { Q> Xmof XmoZm| go nr{ S>V hmo gH$Vm h & (a) Bg p W{V H$mo `m H$hVo h ? (b) `h p W{V H$~ C n hmoVr h ? (c) Bg Xmof go nr{ S>V `{ $`m| H$mo m`: {Og H$ma Ho$ b|gm| H$s Amd `H$Vm hmoVr h CgH$m Zm_ {b{IE & Bg H$ma Ho$ b|gm| H$m Zm_m {H$V AmaoI It{ME & 3 Amn H$m M Ho$ Xmo gd g_ { _m| H$m Cn`moJ {H$g H$ma H$a|Jo {Oggo {H$ nhbo { _ na Amn{VV H$moB nVbm doV H$me nw O X gao { _ go doV H$me nw O Ho$ $n _| hr {ZJ V hmo ? {H$aU AmaoI ItMH$a Cgo Zm_m {H$V H$s{OE & 3 I S> J 25. `m O Ho$ ag _| {^JmoH$a {ZH$mbr JB H$n S>o H$s {H$gr n >r H$m Cn`moJ {H$gr d X Ho$ narjU Ho$ {bE {H$`m J`m & d X Zo CgH$s J Y H$mo n[ad{V V H$a {X`m & `m O H$m ag {H$g H$ma H$m gyMH$ h ? `hr d X Zrbo {bQ>_g H$mo bmb H$a XoVm h & {Z Z{b{IV Ho$ gmW d X H$s A{^{H $`m Ho$ ojUm| H$mo Xem Zo Ho$ {bE gyMr ~ZmBE : (a) q OH$ H$s H${UH$mE (b) R>mog gmo{S>`_ H$m~m}ZoQ> hmoZo dmbr A{^{H $`mAm| Ho$ amgm`{ZH$ g_rH$aU {b{IE & AWdm {H$ Q>bZ Ob H$s n[a^mfm {b{IE & CXmhaUm| Ho$ $n _| Xmo `m {JH$m| Ho$ amgm`{ZH$ gy {b{IE & `h {H$g H$ma g `m{nV {H$`m Om gH$Vm h {H$ {H $ Q>bZ Ob `m {JH$m| H$s Ad Wm Am a a J _| A Va H$a gH$Vm h ? .31/4/1 18 5 5 22. The refractive index of a medium x with respect to a medium y is 2/3 and the refractive index of medium y with respect to medium z is 4/3. Find the refractive index of medium z with respect to medium x . If the speed of light in medium x is 3 108 ms 1, calculate the speed of light in medium y . 23. 3 A person may suffer from both myopia and hypermetropia defects. (a) What is this condition called ? (b) When does it happen ? (c) Name the type of lens often required by the persons suffering from this defect. Draw labelled diagram of such lenses. 24. 3 How will you use two identical glass prisms so that a narrow beam of white light incident on one prism emerges out of the second prism as white light ? Draw and label the ray diagram. 3 SECTION C 25. A cloth strip dipped in onion juice is used for testing a liquid X . The liquid X changes its odour. Which type of an indicator is onion juice ? The liquid X turns blue litmus red. List the observations the liquid X will show on reacting with the following : (a) Zinc granules (b) Solid sodium carbonate Write the chemical equations for the reactions involved. 5 OR Define water of crystallisation. Give the chemical formula for two compounds as examples. How can it be proved that the water of crystallisation makes a difference in the state and colour of the compounds ? .31/4/1 19 5 P.T.O. 26. (a) (b) 27. 28. (i) gmoZo (Jmo S>) Ho$ dh Xmo JwU {b{IE Omo Bgo Am^yfUm| Ho$ {bE g~go A{YH$ Cn`w $ ~ZmVo h & (ii) CZ Xmo YmVwAm| Ho$ Zm_ {b{IE Omo D$ _m Ho$ g~go A N>o MmbH$ h (iii) CZ Xmo YmVwAm| Ho$ Zm_ {b{IE Omo hWobr na aIZo na {nKb OmVr h & ? Bbo Q >m Z-{~ X g aMZm g{hV Am`Zr `m {JH$ CaO Ho$ ~ZZo H$s `m `m H$s{OE & H $p g`_ Am a Am grOZ Ho$ na_mUw H $_m H$ H $_e: 20 Am a 8 h & (a) _mZd eara Ho$ {bE nmofU `m| Amd `H$ h (b) Amhma Zmb Ho$ ^rVa ^moOZ H$mo H$m Z J{V XmZ H$aVm h (c) _m gmhm[a`m| H$s VwbZm _| emH$mhm[a`m| H$s jw m A{YH$ b ~r `m| hmoVr h (d) `{X OR>a J {W`m bo _m H$m dU Z H$a|, Vmo `m hmoJm 5 ? ? ? ? 5 {H$gr nw n _| {ZfoMZ H$mo Xem Zo H$m d N> AmaoI It{ME Am a Cg na (a) namJZbr, (b) Za OZZ-H$mo{eH$m Am a (c) _mXm OZZ-H$mo{eH$m H$mo Zm_m {H$V H$s{OE & nw n _| {ZfoMZ H$s {H $`m H$s `m `m H$s{OE & {ZfoMZ Ho$ n MmV (i) A S>me` Am a (ii) ~rOm S> H$m `m hmoVm h ? 5 AWdm (a) `m dZma ^ {H$go H$hVo h (b) _mZd Za OZZ V _| ZrMo {XE JE ^mJm| Ho$ H$m`m] H$m g jon _| dU Z H$s{OE (i) d fU (ii) ewH $me` (iii) ewH $dm{hH$m (iv) _y _mJ (c) d fU CXa Jwhm Ho$ ~mha p WV `m| hmoVo h (d) C boI H$s{OE {H$ ewH $mUw _mXm OZZ-H$mo{eH$m H$s Amoa {H$g H$ma J{V H$aVo h & .31/4/1 ? 20 : ? 5 26. (a) (i) Write two properties of gold which make it the most suitable metal for ornaments. (b) 27. 28. (ii) Name two metals which are the best conductors of heat. (iii) Name two metals which melt when you keep them on your palm. Explain the formation of ionic compound CaO with electron-dot structure. Atomic numbers of calcium and oxygen are 20 and 8 respectively. (a) Why is nutrition necessary for the human body ? (b) What causes movement of food inside the alimentary canal ? (c) Why is small intestine in herbivores longer than in carnivores ? (d) What will happen if mucus is not secreted by the gastric glands ? 5 5 Draw a neat diagram showing fertilisation in a flower and label (a) Pollen tube, (b) Male germ cell and (c) Female germ cell, on it. Explain the process of fertilisation in a flower. What happens to the (i) ovary and (ii) ovule after fertilisation ? 5 OR (a) What is puberty ? (b) Describe in brief the functions of the following parts in the human male reproductive system : (i) Testes (ii) Seminal vesicle (iii) Vas deferens (iv) Urethra (c) Why are testes located outside the abdominal cavity ? (d) State how sperms move towards the female germ cell. .31/4/1 21 5 P.T.O. 29. {H$gr Eogo n[anW H$m `d Wm AmaoI It{ME {Og_| 2 V Ho$ VrZ gobm| H$s ~ Q>ar, nm d _| g `mo{OV 10 , 20 VWm 30 Ho$ VrZ {VamoYH$m| H$m g `moOZ, EH$ bJ Hww $Or VWm EH$ Eo_rQ>a, g^r loUr _| g `mo{OV h & Bg n[anW H$m Cn`moJ H$aHo$ {Z Z{b{IV H$m _mZ kmV H$s{OE : (a) `oH$ {VamoYH$ go dm{hV Ymam (b) n[anW _| dm{hV Hw$b Ymam (c) n[anW H$m Hw$b ^mdr {VamoY 5 AWdm {H$gr 6 V H$s ~ Q>ar go Xmo gd g_ {VamoYH$, {OZ_| `oH$ H$m {VamoY ~mar-~mar go nhbo (i) loUr _|, Am a {\$a (ii) 15 h , nm d _| g `mo{OV {H$E JE h & `oH$ H$aU 5 _| {VamoYH$m| Ho$ g `moOZ mam Cn^w $ e{ $ Ho$ AZwnmV H$m n[aH$bZ H$s{OE & 30. (a) boq_J H$m dm_-h V {Z`_ {b{IE & (b) h_ AnZo Kam| _| {Og {d wV Ymam H$m Cn`moJ H$aVo h CgHo$ VrZ {d{e Q> bjUm| H$s gyMr ~ZmBE & (c) `y O `m hmoVm h ? Bgo gwajm `w{ $ `m| H$hVo h (d) YmVw Ho$ AmdaU dmbo {d wV gm{Y m| H$mo ^yg n{H $V H$aZm `m| Amd `H$ h .31/4/1 22 ? ? 5 29. Draw a schematic diagram of a circuit consisting of a battery of 3 cells of 2 V each, a combination of three resistors of 10 , 20 and 30 connected in parallel, a plug key and an ammeter, all connected in series. Use this circuit to find the value of the following : (a) Current through each resistor (b) Total current in the circuit (c) Total effective resistance of the circuit 5 OR Two identical resistors, each of resistance 15 , are connected in (i) series, and (ii) parallel, in turn to a battery of 6 V. Calculate the ratio of the power consumed in the combination of resistors in each case. 30. 5 (a) State Fleming s Left-hand rule. (b) List three characteristic features of the electric current used in our homes. (c) What is a fuse ? Why is it called a safety device ? (d) Why is it necessary to earth metallic electric appliances ? .31/4/1 23 5 P.T.O.

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