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  1. J

    A level Biology: Post your doubts here!

    Anyone can explain Q38 http://papers.xtremepapers.com/CIE/Cambridge%20International%20A%20and%20AS%20Level/Biology%20(9700)/9700_w04_qp_1.pdf Answer 38 is D. I understand why add growth, but don't understand why add other life processes and also respiratory heat losses. Then and also Q39...
  2. J

    A level Biology: Post your doubts here!

    Guys, I'm confused with what you can see using light microscope, In one year, MJ 2012 paper 11, Q1 http://papers.xtremepapers.com/CIE/Cambridge%20International%20A%20and%20AS%20Level/Biology%20(9700)/9700_s12_qp_11.pdf They say we can see mitochondria and starch grain through X400 light...
  3. J

    A level Biology: Post your doubts here!

    Wonderful explanation, thank you so much! (:
  4. J

    A level Biology: Post your doubts here!

    Anyone can help with this http://papers.xtremepapers.com/CIE/Cambridge%20International%20A%20and%20AS%20Level/Biology%20(9700)/9700_w12_qp_12.pdf Q21, 23, 24, 31, 33 and 38? 21B 23A 24A 31B 33D 38C Will really appreciate your help!
  5. J

    A level Biology: Post your doubts here!

    Which statement about the light microscope is correct? A As the smallest distance to see two points as distinct separate points decreases, the resolution also decreases. B If the resolution is 220 nm, then a bacterium 0.2 μm in diameter will not be visible. C If the wavelength of light is 600...
  6. J

    A level Biology: Post your doubts here!

    Which of the following are included in the apoplast pathway? 1 living components 2 plant vacuoles 3 cell walls 4 xylem vessels A 3 only B 1 and 2 only C 3 and 4only D 1,2and 4only Answer is A, why xylem vessels is not included in apoplast?
  7. J

    Chemistry: Post your doubts here!

    The reaction is HCl + KI -> KCl + HI. No I2 form, hence is colourless as HI is a colourless solution
  8. J

    Chemistry: Post your doubts here!

    Answer is 3:1 As propane CH3-CH2-CH3 there's total 6 H atom at the side C, but only 2 H atom at the C-2. Hence the chance of getting replace the H with C-1 will be 6 which form 1 chloropropane , and centre will be 2 which form 2 chloropropane, 6:2 Hence is 3:1 (: hope this helps
  9. J

    Chemistry: Post your doubts here!

    35 Solids W, X, Y and Z are compounds of two different Group II metals. Some of their applications are described below. Compound W is used as a refractory lining material in kilns. Compound X is used as a building material. It can also be heated in a kiln to form compound Y. When Y is hydrated...
  10. J

    Chemistry: Post your doubts here!

    8 Which compound is the only gas at room temperature and pressure? A CH3CH2CH2NH2 Mr = 59.0 B CH3CH2CH2OH Mr = 60.0 C CH2OHCH2OH Mr = 62.0 D CH3CH2Cl Mr = 64.5 Answer is D. Why? :o
  11. J

    Physics: Post your doubts here!

    18. Conservation of energy 1/2mv^2 = mgh + 1/2mv^2 Cancel all the m (28)^2/2 = (9.81)(22) + v^2/2 Then u should be able to calculate the v 21. The key word is CONSTANT RATE OF FLOWING OF WATER Hence there will be no increase in velocity along X to Y But because water is forced to flow...
  12. J

    Chemistry: Post your doubts here!

    An organic compound, Z, will react with calcium metal to produce a salt with the empirical formula CaC4H6O4. What could be the identity of Z? 1 ethanoic acid 2 butanedioic acid 3 methylpropanedioic acid Answer is 1 only. Why?
  13. J

    Physics: Post your doubts here!

    29. As u put a screen to view ur interference pattern, u will definitely put at XY 31. U need to draw the positive and negative charge of the electric field. Which is positive on top, negative at bottom due to the direction of the electric field. Hence positive part of the Rod move to negative...
  14. J

    Chemistry: Post your doubts here!

    Solids W, X, Y and Z are compounds of two different Group II metals. Some of their applications are described below. Compound W is used as a refractory lining material in kilns. Compound X is used as a building material. It can also be heated in a kiln to form compound Y. When Y is hydrated, it...
  15. J

    Chemistry: Post your doubts here!

    A solution of Sn2+ ions will reduce an acidified solution of MnO – ions to Mn2+ ions. The Sn2+ ions are oxidised to Sn4+ ions in this reaction. How many moles of Mn2+ ions are formed when a solution containing 9.5 g of SnCl 2 (Mr: 190) is added to an excess of acidified KMnO4 solution? A 0.010...
  16. J

    Chemistry: Post your doubts here!

    An element X and compound YZ react separately with acid as shown. X(s) + 2H+(aq) → X2+(aq) + H2(g) YZ(s) + 2H+(aq) → Y2+(aq) + H2Z(g) When 1.0 g of either X or YZ is reacted with an excess of acid, the total volume of gas formed is the same. Which statements are correct? 1. Ar(X) = Mr(YZ)...
  17. J

    Chemistry: Post your doubts here!

    How to do? Answer is D
  18. J

    Chemistry: Post your doubts here!

    Answer is B. Why answer can't be D? It is also correct right?
  19. J

    Physics: Post your doubts here!

    U imagine ur hand curve into the same shape, u will realised the part of Z is a compression. Just like when u bend a eraser, there will be a tension on top, but compression below
  20. J

    Physics: Post your doubts here!

    Just found out how to do 2nd one, Use formula s=ut + 1/2at^2 Firstly x = 0 + 1/2a(t1)^2 Next x + h = 1/2a(t2) ^2 Sub together 1/2a(t1)^2 + h = 1/2a(t2)^2 And I think u know how to move the rest into correct places (: Thanks a lot!
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