X SCIENCE SA II 3 & 5 MARKS SAMPLE PAPER 4

14.    (a)     What  is meant by magnification in the context  of image  formation by mirror and  lenses  ?                                                                                                                                  

(b)     Power of a lens is + 5 D.  What  is the focal length  and  nature of the lens ?

15.    A person cannot  see objects less than  40 cm from  his eyes clearly. Name  the defect  of vision  he is  suffering from.   Calculate the  power of the  lens  he should use  to read  a book  at 25 cm distance from  his eyes.   Draw  a ray diagram for correction of the defect using  the lens.

16.    (a)     Draw  a labelled diagram to show  the refraction of light  through a glass  slab.             

(b)     Refractive  index  of the diamond is 2.42, what  does  it mean  ?

17.    Write  the name  of following compounds :                                                                                       

(a)     CH₃  CH₂-C ≡ CH (b)     CH₃  CH₂OH  (c)     CH₃COCH₃

18.    Two carbon  compounds A and  B have  the molecular formula C₃H₈  and  C₃H₆  respectively.

(a)     Which  one of the two is most  likely to show  addition reaction ?   Justify your answer.

(b)     Explain  with  the help  of chemical  equation, how  an addition reaction is useful in vegetable ghee  industry.

19.    Explain  in brief how  is the sex of a newborn individual genetically determined.                

20.    Illustrate Mendel’s experiment to show  that  traits  may  be dominant or recessive  by taking  tall/short plants as a character in garden pea.

21.    (a)     Distinguish between homologous and  analogous organs.                                            

(b)     State one evidence of organic  evolution.

22.    (a)     Why  is vegetative propagation practised for growing some  types  of plants ?              

(b)     Name  the different parts  of a flower  that  has  germ  cells.

(c)     List any  two  agents of pollination.

23.    Name  the type  of mirror (s) that  should be used                                                                             

(i)      as a rear  view  mirror

(ii)     by the dentists

Also draw ray diagram (s) and  mention the reason (s) for their  use.

OR

(a)     Name  the type  of lens that  can be used  as magnifying glass.   Give reason (s) and draw a ray  diagram to support your  answer.

(b)     Draw  ray diagrams to show  position and  nature of the image  formed by a

(i)      Convex  mirror when the object is at infinity. (ii)     Concave mirror when the  object is

(a)     at C             (b)     between F and  C

24.    (a)     Write  chemical  equation of the  reactions of ethanoic acid  with                                        

(i)      sodium      (ii)     sodium carbonate       (iii)    ethanol in  the  presence of Conc.H₂SO₄

(b)     State the  role  of concentrated sulphuric acid  in the  esterification reaction.

(c)     Write  one use  of ethanoic acid.

OR

(a)     Why  does  carbon  form  largest  number of compounds ?  Give two  reasons.

(b)     Why  are some  of these  called  saturated and  the other  unsaturated compound ?

(c)     Which  of these  two  is more  reactive and  why  ?

(d)     Draw  the  structures of the  following compounds

(i)      Bromopentane             (ii)     Hexanal

25.    Draw  a neat  diagram of the  human female  reproductive system and  label  the  parts which  perform the  following functions.

(a)     production of eggs  (b)     site of fertilization (c)     site of implantation (d)     entry  of sperms

What  happens when the egg is not fertilized ?

OR

(a)     State any  two  changes seen in girls at the time  of puberty

(b)     How  does  the embryo get nourishment inside  the mother’s body  ?  State in brief. (c)     List any  two  commonly adopted, contracepotive methods.