Physics-Marking Scheme/Physics-MS-P2-O.N-09.pdf - Ourpgs.com

Page 4 Mark Scheme: Teachers’ version Syllabus PaperGCE O LEVEL – October/November 2009 5054 02Section B9 (a) (i) 100 – 22 or 78 C1(Q =)mc∆T or 35 × 4200 × 78 C11.1/1.1466/1.15 × 10 7 J A1(ii) (t =)E/P or P = E/t or 1.15 × 10 7 /2600C14.4/4.41/4.42 × 10 3 s A1(iii) heat escapes/lost (to kitchen) or heat to heat the boiler/heateror not all heat ends up in water or heat to cause evaporationor used as latent heat (not heat wasted) B1 [6](b) (i) hot/warm water expands (not molecules expand) B1density (of hot/warm water) decreasesB1hot/warm water risesB1convection current/circulation or cold water sinksB1mixes water (max 4) B1(ii) metal/steel is (good) conductor/poor insulator or plastic is poor conductor/insulatorB1more heat transferred through steel/less through plastic or heat transferred morequickly through steel/less quickly through plastic B1 [6](c) (i) evaporation OR condensation B1(ii) any two pointsonly occurs at surfaceboiling needs heat/occurs at any temperature condensation releases heat B1produces coolingboiling: liquid to gas/no bubbles B2 condensation: gas to liquid B1 [3][Total: 15]10 (a) (i) (W =)mg or 0.5 × 3.7 C11.8/1.85/1.9 N A1(ii) 3.7 m/s 2 not N/kgB1(iii) (KE =) ½mv 2C1½ × 0.50 × 3.2 2C12.6 or 2.56 J A1 [6](b) (i) A compares/measures (unknown and known) masses/amount of matter B1B measures/is dependent on weight/force of gravity (and hence mass obtained) B1Mars weights/forces of gravity are less than/different from (Earth)B1(ii) A or lever arm balance or balance with discs B1 [4]© UCLES 2009www.ourpgs.com