Sunday, November 25, 2007


X Science (Theory)
Time – 21/2 Max.Marks - 60
General Instructions :-
1. The question paper comprises of two sections A and B. You are to attempt both the sections.
2. All questions are compulsory.
3. There is no overall choice. However internal choice has been provided in the some questions. You are the attempt only one options in such questions .
4. You are advised to attempt all the question of section A and section B separately.
5. Questions number 1-6 in section A and 17-19 in section B are very short answer questions and carry one marks each
6. Question number 7-10 in section A and 20-24 in section B are short answer questions and carry two marks each.
7. Question number 11-14 in section A and 25-26 in section B are short answer questions and carry three marks each.
8. Question number 15 and 16 in section A and 27 in section B are short answer questions and carry five marks each.

Name one metal which displaces copper from copper sulphate solution and one metal which does not.
Why does carbon form largest number of compounds?
Name the organic compound used as preservative in pickle and has molecular formula C2H4O2 .
What constitutes the field of a magnet?
Why is tungsten metal selected for making filaments of incandescent lamp bulbs?
Two thin lenses of power +2.5 D and -2.5 D are placed in contact. Find the power and focal length of combination.
Write the process to convert an unsaturated hydrocarbon into saturated hydrocarbon. Give its industrial application.
What do you mean by a precipitation reaction? Explain giving example.
Observe the following diagram and answer questions given below :-

What the distance OF is called?
Write the position and nature of the image formed.
Refractive index of water is 4/3 and glass is 3/2 with respect to air. What is refractive index of glass with respect to water?
Atomic radii of the elements of the second period are given below:-
Period – II (elements)
Atomic Radii (pm)

Arrange them in decreasing order of their atomic radii.
Which elements have the largest and smallest atoms?
How does the atomic radius change as you go from left to right in a period?
(a) When does an electric short circuit occur?
(b) Why is it necessary to earthing appliances?
Six solutions A,B,C,D,E and F when tested with universal indicator showed pH as 4,1,11,2,7 and 9 respectively. Which solution -
a. Neutral
b.Strong acid
c.Strong base
d. Weak base
f. Arrange them in order of increasing hydrogen ion concentrations.
An object 3 cm high is placed at a distance of 20 cm in front of a convex lens of focal length 12 cm. Find the position, Nature and size of the image formed.
What are factors affecting the magnetic field produced by a current carrying conductor? Write the magnetic field due to infinitely long current carrying conductor.
OR Draw the schematic diagram of a circuit containing the following electrical components:- (a) a resistance (b) a voltmeter (c) a cell (d) an electric bulb (e) an ammeter (f) plug key. Write the formula to calculate the effective resistance of two resistances connected in series and parallel.
Write the chemical name and formula of Plaster of Paris. Write its two uses and its important properties.
Explain why :-
(i) 24 carrot gold cannot be used for making ornaments.
(ii) Aluminium is used for making cooking utensils.
(iii) Conc. HNO3 can be stored in Aluminium container.
(iv) Aluminium is used for making electrical wires.
(v) Aluminium cannot be extracted by reducing alumina with carbon.


Name the juice stored in gallbladder. Where it is secreted?
What is the cause of muscle fatigue after hard physical work?
What is acid rain? Name the gases responsible for acid rain.
Why we say energy flow in the biosphere is ‘Unidirectional’.
Suggest any two ways to strike a balance between environment and development.
What is nucleotide? Name the type of nucleotide present in DNA and RNA.
Define the terms unisexual and bisexual giving one example of each.
Write one difference between the following :-
Arteries & Veins.
Role of chloroplast & mitochondria.

Draw a diagram of a nerve cell and label the following parts :-
Ranvier’s node.
State the two vital functions of the human kidney. Name the procedure used in the working of artificial kidney.
Given below is a schematic representation of circulatory system in man. Study the diagram and answer the following:-

i. Label the parts 1-6
ii. What is the specific name of blood circulation between heart and lung?
iii. Name covering which protect the heart. OR
What are fossils? Give two uses of fossils. How does the study of fossils provide evidence in favour of organic evolution?