Tiêu đề Varsity Weekly-5 (Set-B) Solution (1).pdf ✅

Varsity Weekly-05 [B(Solution)] wm‡jevm: gnvKl© I AwfKl© + †gŠ‡ji ch©ve„Ë ag© I ivmvqwbK eÜb + RwUj msL ̈v + cÖvYxi cwiwPwZ I †kÖwYweb ̈vm + wUmy ̈ I wUmy ̈Zš¿ + evsjv (evqvbœi w`b ̧‡jv, †deaæqvwi 1969, mgvm, mvivsk) + Bs‡iwR (voice changing, modals and semi modals, articles, Antonyms, Group verbs, paragraph writing) c~Y©gvb: 100 †b‡MwUf gvK©: 0.25 mgq: 1 NÈv 30 wgwbU MCQ c`v_©weÁvb (Physics) 1. †Kv‡bv GKwU e ̄‘‡K Zvi gyw3‡e‡Mi KZ ̧Y †e‡M wb‡ÿc Ki‡j K...wÎg DcMÖ‡n cwiYZ n‡e? [How many times of its escape velocity will an object become an artificial satellite?] 2ve 1 2 ve 1 2 ve 2 ve DËi: 1 2 ve e ̈vL ̈v: v = GM r ve = 2GM r v ve = GM r 2GM r  v = 1 2  ve 2. c„w_ex †Kvb e ̈w3‡K F e‡j Ges e ̈w3 c„w_ex‡K f e‡j AvKl©Y Ki‡j †KvbwU mwVK? [If the earth attracts a person with force F and the person attracts the earth as f, which is correct?] f > F F > f F >> f F = f DËi: F = f 3. c„w_ex‡Z GKwU e ̄‘i IRb 360 kg-wt. g1⁄2j MÖ‡ni fi I e ̈vmva© h_vμ‡g c„w_exi 1 9 Ges 1 2 ̧Y n‡j, g1⁄2jMÖ‡ni c„‡ô e ̄‘wUi IRb KZ? [An object on Earth weighs 360 kg-wt. If the mass and radius of Mars are 1 9 and 1 2 times the mass of Earth and radius respectively, what is the weight of the object on the surface of Mars?] 160 kg - wt 180 kg - wt 100 kg - wt 20 kg - wt DËi: 160 kg - wt e ̈vL ̈v: Wm We = GMm R 2 m GMe R 2 e =    Mm Me      Re Rm 2 = 1 9  4 = 4 9 Wm = 4 9  We = 4 9  360 = 4  40 = 160 kg – wt 4. 1 kg f‡ii `ywU e ̄‘‡K ci ̄úi n‡Z 1 m `~i‡Z¡ ̄’vcb Ki‡j Zviv ci ̄úi‡K †h ej Øviv AvKl©Y K‡i Zvi gvb n‡jvÑ [If two objects of mass 1 kg are placed at a distance of 1 m from each other, the force with which they attract each other is –] 6.67  10–11 Nm2 kg–2 6.67  10–7 Nm2 kg–2 6.67  10–11 N 1 N DËi: 6.67  10–11 N e ̈vL ̈v: F = G Mm r 2 = 6.67  10–11 1  1 1 2 = 6.67  10–11 N e‡ji GKK me©`v wbDUb (N)| 5. m f‡ii `ywU DcMÖn A I B h_vμ‡g f‚-c„ô n‡Z 12800 km I 19200 km D”PZvq e„ËvKvi Kÿc‡_ N~Y©vqgvb i‡q‡Q| Zv‡`i wefekw3i AbycvZ KZ? [Two satellites A and B of mass m are moving in circular orbits at altitudes of 12800 km and 19200 km respectively. What is the ratio of their potential energy?] 3 : 4 4 : 3 2 : 1 1 : 3 DËi: 4 : 3 e ̈vL ̈v: U = – GMm R + h  UA UB = R + hB R + hA = 19200 + 6400 6400 + 12800 = 25600 19200 = 4 3  UA UB = 4 3  UA : UB = 4 : 3 6. hw` c„w_exi e ̈vmva© 3% n«vm cvq, Z‡e f‚c„‡ô AwfKl©R Z¡iYÑ [If the Earth's radius decreases by 3%, the gravitational acceleration at the surface is-] 6% e„w× cv‡e 6% n«vm cv‡e 3% e„w× cv‡e 3% n«vm cv‡e DËi: 6% e„w× cv‡e e ̈vL ̈v: g = GM R 2 g g  100% = 2  R R  100%
= 2  3% = 6% e„w× cv‡e 7. †Kvb ̄’v‡b 1 kg wPwb †Kbv jvfRbK? [Where is it profitable to buy 1 kg of sugar?] wbiÿxq A‡j †giæ‡Z 45 Aÿvs‡k †Kv‡bvwUB bq DËi: wbiÿxq A‡j e ̈vL ̈v: †hLv‡b IRb Kg †`Lv‡e, †mLv‡b wPwb †Kbv jvfRbK| g = g –  2 Rcos2   W =  – m 2Rcos2  W me©wb¤œ n‡e, hLb cos Gi gvb me©vwaK n‡e| cos Gi me©vwaK gvb = 1   = 0 [ = 0 n‡j Zv wbiÿxq AÂj|] 8. f‚-c„ô n‡Z m‡e©v”P KZ †e‡M †Kv‡bv e ̄‘‡K wb‡ÿc Ki‡j Zv c„w_exi e ̈vmv‡a©i mgvb D”PZvq †cuŠQv‡e? [How fast will an object be thrown from the earth's surface to reach a height equal to the maximum radius of the earth?]     2GM R 1 2     GM R 1 2     4GM R 1 2     8GM R 1 2 DËi:     GM R 1 2 e ̈vL ̈v: 1 2 mv2 = GMm     1 Ri – 1 Rf  1 2 v 2 = GM     1 R – 1 2R  1 2 v 2 = GM 2R  v = GM R 9. m f‡ii GKwU K...wÎg DcMÖn f‚c„ô n‡Z R D”PZvq Nyi‡Q| hw` gnvKl©xq †ÿÎ cÖvej ̈ g Ges c„w_exi e ̈vmva© R nq, Z‡e H K...wÎg DcMÖ‡ni MwZkw3 n‡eÑ [An artificial satellite of mass m is orbiting at a height R above the Earth's surface. If the gravitational field intensity is g and the radius of the earth is R, the kinetic energy of the artificial satellite will be-] mg R 4 mg R 2 mg R 3 mgR DËi: mg R 4 e ̈vL ̈v: Ek = 1 2 mv2 = 1 2 m GM R + R = 1 2 m GM 2R = 1 2 m GMR 2R2 = 1 4 mgR 10. f‚c„‡ô AwfKl©R Z¡iY g n‡j, c„w_ex c„ô n‡Z †Kv‡bv m f‡ii e ̄‘‡K ax‡i ax‡i c„w_exi e ̈vmv‡a©i mgvb R D”PZvq wb‡q †M‡j K...ZKvR n‡eÑ [If the gravitational acceleration at the surface of the earth is g, an object of mass m is slowly lifted from the surface of the earth to a height R equal to the radius of the earth, the work done will be-] 2 mgR mgR 1 2 mgR 1 4 mgR DËi: 1 2 mgR e ̈vL ̈v: W = Ep2 – Ep1 = – GMm R + R + GMm R = GMm 2R = 1 2 m     GM R 2 R = 1 2 mgR 11. c„w_ex‡K  Mo Nb‡Z¡i •Zwi R e ̈vmv‡a©i GKwU †MvjK wn‡m‡e we‡ePbv Ki‡j Gi c„‡ôi wefe KZ n‡e? [What is the surface potential of the earth if we consider it as a sphere of radius R made of mean density ?] 4 3 R 3 G 3 4 R 3 G – 4 3 R 2 G – 3 4 R 2 G DËi: – 4 3 R 2 G e ̈vL ̈v: Avgiv Rvwb, V = – GM R Avevi, M = 4 3 R 3   V = – G 4R 3  3R = – 4 3 GR2  12. C we›`y‡Z gnvKl©xq †ÿÎ cÖvej ̈ KZ? 3m 4m 5m E1 E2 A B C 1 kg 90 kg 160 kg [What is the gravitational field intensity at point C?] 6.673  10–10 Nkg–1 2  6.673  10–10 Nkg–1 3  6.673  10–10 Nkg–1 6  6.673  10–10 Nkg–1 DËi: 2  6.673  10–10 Nkg–1 e ̈vL ̈v: E1 = 6.673  10–11  90 3 2 = 6.673  10–11  90 9 = 6.673  10–10 Nkg–1 E2 = 6.673  10–11  160 4 2 = 6.673  10–11  160 16 = 6.673  10–10 Nkg–1 E = E 2 1 + E2 2 = 2 (6.673  10–10) 2 = 2  6.673  10–10 Nkg–1 13. m f‡ii GKwU e ̄‘‡K c„w_ex c„ô n‡Z 2R D”PZvq DVv‡j Gi wefe kw3 KZ? [R c„w_exi e ̈vmva©|] [What is the potential energy of an object of mass m when it is lifted to a height of 2R above the earth's surface? [R is the radius of the earth.]] 2GMm 3R 2mgR 3 2 mg 3R K Ges L DfqB DËi: K Ges L DfqB
e ̈vL ̈v: wefekw3, Ep =  R + h R Fdr =  R + h R GMm r 2 dr = GMm     – 1 r R + h R = GMm     – 1 R + h + 1 R = GMm     – 1 R + 2R + 1 R [∵ h = 2R] = 2GMm 3R  Ep = 2mgR 3 14. c„w_exi c„‡ô GKwU e ̄‘i IRb 72 N| c„w_ex c„ô †_‡K c„w_exi e ̈vmv‡a©i A‡a©K D”PZvq IB e ̄‘i IRb KZ n‡e? [An object weighs 72 N on the surface of the earth. What will be the weight of that object at a height of half the radius of the earth from the surface of the earth?] 20 N 30 N 32 N 40 N DËi: 32 N e ̈vL ̈v: GLv‡b, e ̄‘i IRb, mg = 72 N D”PZv, h = R 2 IB D”PZvq AwfKl©R Z¡iY g n‡j, Avgiv Rvwb, g = g R 2 (R + h) 2 = g  R 2    R +  R 2 2 = 4 9 g myZivs, IB D”PZvq e ̄‘wUi IRb, = mg = m  4 9 g = 4 9  mg = 4 9  72 = 32 N 15. AwfKl©xq Z¡iY g I ch©vqKvj T Gi †jLwPÎ †KvbwU? [Which is the graph of gravitational acceleration g and period T?] g T 2 y x O g T 2 y x O g T 2 y x O g T 2 y x O DËi: g T 2 y x O e ̈vL ̈v: ∵ T = 2 L g  T  1 g imvqb (Chemistry) 1. [Cr (H2O)6] 3+ Gi g ̈vM‡bwUK †gv‡g›U KZ? [What is the magnetic moment of [Cr (H2O)6] 3+?] 4 2 15 3 4 4 6 DËi: 15 e ̈vL ̈v: g ̈vM‡bwUK †gv‡g›U,  = n (n + 2) = 3 (3 + 2) = 15 GLv‡b, n AhyM¥ B‡jKUab msL ̈v| 2. Mg(s) + 2X(s)  MgX2(s) MgX2(s) + 2H2O(l)  Mg(OH)2(aq) + CH  CH(g) (K) GLv‡b, X †KvbwU? [Mg(s) + 2X(s)  MgX2(s) MgX2(s) + 2H2O(l)  Mg(OH)2(aq) + CH  CH(g) Here, which is X?] N2 C NH3 Co DËi: C e ̈vL ̈v: Mg †K C mn‡hv‡M DËß Ki‡j MgC2 MwVZ nq hv Mig cvwbi mv‡_ wewμqv K‡i Mg(OH)2 I A ̈vwmwUwjb M ̈vm Drcbœ K‡i| Mg(s) + 2C(s)  MgC2(s) MgC2(s) + 2H2O(l)  Mg(OH)2(aq) + HC  CH(g) 3. ÿviKxq A·vBW †Kvb ̧‡jv? [What are alkaline oxides?] Na2O, FeO Na2O, CO SO2, SiO2 P2O5, NO DËi: Na2O, FeO e ̈vL ̈v: Na2O, FeO ÿviKxq A·vBW P2O5, SiO2, SO2 A¤øxq A·vBW| NO, CO, N2O wbi‡cÿ A·vBW 4. K + , S2– , Cl – Gi AvqwbK AvKvi wb‡Pi †KvbwU? [Which of the following is the ionic form of K + , S2– , Cl – ?] S 2– > K+ > Cl – S 2– > Cl – > K+ Cl – > S2– > K+ Cl – > K+ > S2– DËi: S 2– > Cl – > K+ e ̈vL ̈v: Cl – Gi †P‡q S 2– Gi Kvh©Ki wbDwK¬qvi PvR© cÖfve Kg, ZvB S 2– Gi AvKvi Cl – Gi AvKv‡ii †P‡q eo| Avevi K + Gi Kvh©Ki wbDwK¬qvi PvR© cÖfve †ewk, ZvB K + me‡P‡q †QvU| 5. wb‡Pi †Kvb wjM ̈v‡Ûi bvg bvB‡Uavwmj? [Which of the following ligands is called nitrosyl?] CO NO CN– NH3 DËi: NO e ̈vL ̈v: CO  Kve©wbj NO  bvB‡Uavwmj CN–  mvqv‡bv NH3  A ̈vg&wgb| 6. S 2– , P3– , Ca2+, Sc3+ Gi AvqbxKiY kw3i μg †KvbwU? [What is the order of ionization energy of S 2– , P3– , Ca2+ , Sc3+?] Sc3+  Ca2+  P 3–  S 2– P 3–  S 2–  Ca2+  Sc3+ S 2–  Ca2+  P 3– Sc3+ Sc3+  Ca2+  S 2–  P 3– DËi: Sc3+  Ca2+  S 2–  P 3– e ̈vL ̈v: GLv‡b, Avqb ̧‡jvi cvigvYweK e ̈vmv‡a©i μg P 3–  S 2–  Ca2+  Sc3+ | AvqbxKiY kw3i †ÿ‡Î, cigvYy ev Avq‡bi cvigvYweK AvKvi evo‡j AvqbxKiY kw3i gvb K‡g Ges cvigvYweK AvKvi Kg‡j AvqbxKiY kw3i gvb ev‡o| GLv‡b, Avqb ̧‡jvi g‡a ̈ Sc3+ Gi AvKvi me‡P‡q Kg nIqvq Sc3+ Gi AvqbxKiY kw3 me‡P‡q †ewk| AvqbxKiY kw3i μg n‡jv: Sc3+  Ca2+  S 2–  P 3– |
7. La Gi 4f AiweUv‡j KqwU B‡jKUab i‡q‡Q? [How many electrons are there in 4f orbital of La?] 0 2 1 3 DËi: 0 e ̈vL ̈v: D”P cvigvYweK msL ̈vwewkó †g.jmg~‡ni †ÿ‡Î nf I (n + 1)d AiweUv‡ji kw3 cv_©K ̈ Lye Kg nq| ZvB La Gi 57Zg B‡jKUabwU 4f G bv wM‡q 5d †Z hvq| 8. [Cr(NH3)6] 3+ Gi †PŠ¤^Kxq ag© †KvbwU? [What is the magnetic property of [Cr(NH3)6] 3+?] c ̈vivg ̈vM‡bwUK Wvqvg ̈vM‡bwUK †d‡ivg ̈vM‡bwUK `~e©j g ̈vM‡bwUK DËi: c ̈vivg ̈vM‡bwUK e ̈vL ̈v: [Cr(NH3)6] 3+ Gi avZe Avqb Cr3+ Cr3+ 24 : [Ar] 3d1 + 1 + 1 wZbwU we‡Rvo B‡jKUab _vKvq, GwU c ̈vivg ̈vM‡bwUK| 9. wb‡Pi †Kvb †hŠMwU PZz ̄ÍjKxq AvK...wZi bq? [Which of the following compounds is not tetrahedral in shape?] CH4 NH+ 4 CCl4 SF4 DËi: SF4 e ̈vL ̈v: SF4 Gi AvK...wZ weK...Z PZz ̄ÍjKxq/K-Shape/see saw shape| CH4, NH+ 4 , CCl4 Gi AvK...wZ PZz ̄ÍjKxq| 10. wb‡Pi †KvbwU H-eÜb MVb K‡i? [Which of the following forms H-bond?] i. H2O ii. C6H5OH iii. CH3 – COOH i i, iii i, ii i, ii, iii DËi: i, ii, iii e ̈vL ̈v: HF, H2O, CH3OH, CH3 – COOH-G H-eÜb we` ̈gvb| 11. POCl3 †hŠ‡M †K›`axq cigvYyi †Kvb msKiY N‡U? [In the compound POCl3, which hybridization of the central atom occurs?] sp3 d sp2 sp3 sp DËi: sp3 e ̈vL ̈v: x = 1 2 (5 + 3 + 0 – 0) = 1 2  8 = 4 = sp3 12. [Ni(CN)4] 2– Gi AvK...wZ wKiƒc? [What is the shape of [Ni(CN)4] 2– ?] mgZjxq eM©vKvi PZz ̄ÍjKxq w·KvYvKvi wØ-wcivwgWxq AóZjKxq DËi: mgZjxq eM©vKvi e ̈vL ̈v: GLv‡b, Ni Gi RviY msL ̈v x n‡j, x + (– 1)  4 = – 2 x = + 2 ↿⇂ ↿⇂ ↿⇂ ↿⇂ 28Ni2+  [Ar] 3d8 4s0 : CN– CN– : : : CN– CN–  msKivqb dsp2 Ni2+ CN– CN– CN– CN– mgZjxq eM©vKvi 13. [Co(NH3)4Cl2]Cl †hŠ‡Mi Co Gi mwbœ‡ek msL ̈v KZ? [What is the co-ordination number of Co in the compound [Co(NH3)4Cl2]Cl?] 2 4 6 7 DËi: 6 e ̈vL ̈v: †K›`axq †g.j Co Gi d, p I s-AiweUvj NH3 4wU I Cl 2wU gy3‡Rvo B‡jKUab `vb K‡i mwbœ‡ek eÜb MVb K‡i myZivs †h.MwU‡Z †gvU 6wU mwbœ‡ek eÜb i‡q‡Q| 14. Mjbv‡1⁄4i Aatμg Abymv‡i wb‡Pi †KvbwU mwVK? [Which of the following is correct descending order of melting point?] NaCl  MgCl2  AlCl3 AlCl3  MgCl2  NaCl AlCl3 > MgCl2  NaCl NaCl > MgCl2  AlCl3 DËi: NaCl  MgCl2  AlCl3 e ̈vL ̈v: dvRv‡bi wbqg Abyhvqx A ̈vbvqb GKB n‡j hvi K ̈vUvq‡bi AvKvi †QvU Zvi †cvjvivqb †ewk| d‡j †mB †h.‡Mi AvqwbK •ewkó ̈ Kg n‡e| Mjbv‡1⁄4i μg: NaCl  MgCl2  AlCl3 (Aatμg) AlCl3  MgCl2  NaCl (EaŸ©μg)| 15. BrF5 Gi R ̈vwgwZK AvK...wZ †KvbwU? [What is the geometric shape of BrF5?] Octahedral Square Pyramidal Trigonal Bi-Pyramidal Square Planar DËi: Square Pyramidal e ̈vL ̈v: BrF5 Gi †K›`axq †g.j Br Gi msKivqb X n‡j, X = 1 2 [7 + 5] = 6 = sp3 d 2 wKš‘, GLv‡b gy3‡Rvo e – Gi msL ̈v, l.p = 1 ZvB BrF5 Gi AvK...wZ Octahedral bv n‡q Square Pyramidal nq| F F F F F Br MwYZ (Mathmatics) 1. (1 + ) 7 = A + B n‡j, A Ges B h_vμ‡gÑ [If (1 + ω)7 = A + B, A and B are respectively-] 0, 1 1, 1 1, 0 – 1, 1 DËi: 1, 1 e ̈vL ̈v: (1 + ) 7 = A + B  (–  2 ) 7 = A + B  –  14 = A + B  1 += A + B  A = 1 I B = 1