CBSE Class-10 Exam 2016 : Marking Scheme, Science (Delhi)
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CBSE Class-10 Exam 2016 : Marking Scheme, Science (Delhi)
CBSE Class-10 Exam 2016 : Science (Delhi) Set -1
MARKING SCHEME
CLASS X – DELHI
CLASS X – DELHI
Code No. 31/1/1
Expected Answer/ Value point Marks Total
SECTION – A
Q 1. (i) C3H6 ½
(ii) C5H8 ½ 1
Q2. Leaf (notches) 1 1
Q3. Natural ecosystem – Forest/ Lake/ Pond/ River (Any two) ½+½ 1
Q4. When the object is placed in front of the mirror –
(i) between its pole and focus ½
(ii) between the focus and centre of curvature ½
In case (i) the image is virtual and erect ½
In case (ii) the image is real and inverted ½ 2
(i) between its pole and focus ½
(ii) between the focus and centre of curvature ½
In case (i) the image is virtual and erect ½
In case (ii) the image is real and inverted ½ 2
Q5. Advantages of watershed management –
(i) mitigates drought and floods
(ii) increase the life of the dams and reservoirs downstream
(iii) increases the biomass production and thereby the income of the watershed community.
(iv) helps in maintaining ecological balance by scientific conservation of soil and water. or any other (Any four) 4 x ½ 2
(i) mitigates drought and floods
(ii) increase the life of the dams and reservoirs downstream
(iii) increases the biomass production and thereby the income of the watershed community.
(iv) helps in maintaining ecological balance by scientific conservation of soil and water. or any other (Any four) 4 x ½ 2
Q6.
- In West Bengal the Sal forests had been very badly degraded. ½
- A forest officer involved villagers in protection of Sal forest and gave them employment in silviculture and harvesting operations. ½
- Villagers were allowed to collect firewood and fodder on a nominal payment. ½
- Within a period of 10 years the previously worthless forests became valuable. ½ 2
Q7.
- Covalent compounds are those compounds which are formed by sharing of electrons between two atoms / which contain covalent bonds. 1
- Covalent compounds are different from ionic compounds because the ionic compounds are formed by the transference of electrons. ½
- Three characteristics of covalent compounds:
(i) Generally have low melting and boiling points.
(ii) Generally insoluble or less soluble in water but soluble in organic solvents.
(iii)Do not conduct electricity. (Or any other characteristic) (Any three) 3 x ½ 3
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Courtesy: CBSE