KENDRIYA VIDYALAYA SANGATHAN
BHUBANESWAR REGION
1st PRE BOARD EXAMINATION (2024-25)
CLASS X
Science (086)
Max. Marks: 80 Time Allowed: 3 hours
General Instructions:
1. All questions would be compulsory. However, an internal choice of approximately 33% would be
provided. 50% marks are to be allotted to competency-based questions.
2. Section A would have 16 simple/complex MCQs and 04 Assertion-Reasoning type questions
carrying 1 mark each.
3. Section B would have 6 Short Answer (SA) type questions carrying 02 marks each.
4. Section C would have 7 Short Answer (SA) type questions carrying 03 marks each.
5. Section D would have 3 Long Answer (LA) type questions carrying 05 marks each.
6. Section E would have 3 source based/case based/passage based/integrated units of
assessment (04 marks each) with sub-parts of the values of 1/2/3 marks.
Section-A
Question 1 to 16 are multiple choice questions. Only one of the choices is correct. Select
and write the correct choice as well as the answer to these questions.
1. Gustatory receptors are able to detect:- 1
a) Touch b) Smell c) light d) Taste
2. Solid calcium oxide reacts vigorously with water to form calcium hydroxide 1
accompanied by the liberation of heat. From the information given above it may be
concluded that this reaction is:-
a) Endothermic and pH of the solution is more than 7.
b) Exothermic and pH of the solution is 7.
c) Endothermic and pH of the solution is 7.
d) Exothermic and pH of the solution is more than 7.
3. The strength of magnetic field inside a long current carrying straight solenoid is 1
a) More at the ends than at the centre
b) Minimum at the middle
c) Same at all points
d) Found to increase from one end to the other
4. Amongst the following group of materials the group which contains only 1
biodegradable materials is:-
a) Polythene, Soap, Wool c) Plastic, Leather, Grass
b) Glass, Aluminium, Neem Leaves d) Wood, Leather , Paper
5. The image formed by a concave mirror of focal length 25 cm is real and of 1
magnification -1. In this case the distance between the objet and its own image is:-
a) 50 cm b) zero c) 25 cm d) 100 cm
6. 1
In the following diagram, the path of a ray of light
passing through the glass prism is shown. In this figure the angle of incidence, the
angle of emergence and the angle of deviation are-:
a) X, R and Q
b) X, R and P
c) Y, Q and P
d) Y, T and Q
7. A hydrocarbon which contains two C-C single bonds and one C=C double bond is: 1
a) Ethene b) Benzene c) Butene d) Propene
8. Decomposers are not included in the food chain. The correct reason for the same 1
is because decomposers:-
a) Act at every tropic level of the food chain.
b) Do not breakdown organic compounds.
c) Convert organic material to inorganic forms.
d) Release enzymes outside their body to convert organic material to
inorganic forms.
9. An element X reacts with O2 to give a compound with a high melting point. This 1
compound is also soluble in water. The element ‘X’ is likely to be :-
a) Iron b) Carbon c) calcium d) silicon
10. Solder is an alloy of : 1
a) Cu and Zn b) Pb and Sn c) Pb, Sn and Zn d) Al and Sn
11. Which of the following statements about the given reaction are correct? 1
3Fe(s) + 4H2O (g) →Fe3O4(s) + 4H2 (g)
i) Iron metal is getting oxidized.
ii) Water is getting reduced.
iii) Water is acting as a reducing agent.
iv) Water is acting as an oxidising agent.
a) i, ii and iii b) i , ii and iv c) iii and iv d) ii and iv
12. The maximum resistance of a network of five identical resisters of 1/5 ohm each 1
can be :-
a) 1 ohm b) 0.5 ohm c) 0.25 ohm d) 0.1 ohm
13. In plants, A stomata closes when: 1
i) It needs CO2 for photosynthesis.
ii) It does not need CO2 for photosynthesis.
iii) Water flows into the guard cells.
iv) Water flows out of the guard cells.
a) Only ii b) ii and iii c) i and iv d) ii and iv
14. Walking in a straight line and riding a bicycle are the activities which are possible 1
due to a part of the brain. Choose the correct location and name of this part from
the given table:-
Part of brain Name
a Fore brain Cerebrum
b Mid brain Hypothalamus
c Hind brain Cerebellum
d Hind brain Medulla
15. Select from the following the conditions responsible for the rapid spread of bread 1
mould on a slice of bread:-
i) Formation of large number of spores.
ii) Presence of moisture and nutrients in bread.
iii) Low Temperature
iv) Presence of hyphae
a) i and ii b) ii and iv c) Only ii d) ii and iii
16. If homozygous tall plant cross with heterozygous tall plant, What will be the 1
percentage of tall and dwarf in their offspring?
a) 75 tall and 25 dwarf c) 100 tall and no dwarf
b) 25 tall and 75 dwarf d) 50 tall and 50 dwarf
Question No. 17 to 20 consist of two statements – Assertion (A) and Reason (R). Answer
these questions by selecting the appropriate option given below:
A. Both A and R are true, and R is the correct explanation of A.
B. Both A and R are true, and R is not the correct explanation of A.
C. A is true but R is false.
D. A is false but R is true
17. Assertion (A) : Magnetic field lines never intersect each other. 1
Reason (R) : The magnetic lines arise from north pole to south pole of the
magnet..
18. Assertion (A) : Ozone (O3) is a molecule formed by the three atoms of oxygen. 1
Reason (R) : Ultraviolet sunlight breaks apart an oxygen molecule to form two
separate oxygen atoms. Then each oxygen atom combines with oxygen molecule
to form ozone.
19. Assertion (A) : In human, there is a complex respiratory system. 1
Reason (R) : Human skin is permeable to gases.
20. Assertion (A) :After white washing the walls, a shiny white finish on walls is 1
obtained after two to three days.
Reason (R) : Calcium oxide reacts with carbon dioxide to form calcium hydrogen
carbonate which gives shiny white finish.
Section-B
Question No. 21 to 26 are very short answer questions
21. Attempt either option A or B. 2
A.
List the role of each of the following in our digestive system:-
a) Mucus b) Trypsin
OR
B.
Name the following :
a) The three carbon molecule that is formed due to break down of glucose
during respiration.
b) The nitrogenous waste that is removed from the blood in our kidneys.
22. Translate the following statements into chemical equations and balance them. 2
a) Hydrogen sulphide gas burns in air to give water and sulphur dioxide.
b) Silver bromide on exposure to sunlight decomposes into Silver and
Bromine.
23. What is Placenta? Explain its function in humans. 2
24. Attempt either option A or B. 2
A.
Draw a labelled ray diagram to show the path of a ray of light incident obliquely on
one face of a glass slab. Show the angle of incidence, the angle of emergence and
the lateral displacement.
OR
B.
If the image formed by mirror for all positions of the object placed in front of it
always virtual and diminished. State the type of mirror. Draw a ray diagram in
support of your answer.
25. Draw the structure of the following compounds indicating the functional group 2
present in each
a) Propanol b) Butanoic acid
26. Why do we need to clean aquarium but not a pond? Explain. 2
SECTION C
Question No. 27 to 33 are short answer questions
27. (a) A non metal X exists in two different forms Y and Z. Y is the hardest natural 3
substance whereas Z is a good conductor of electricity. Identify Y and Z. (1+2)
(b) Show the electron dot structures of the formation of CaO and MgCl2.
28. Attempt either option A or B. 3
A.
List the important products of the chlor-alkali process. Write one important use of
each product.
OR
