10th Science Paper Solutions Set 1 : CBSE Abroad Previous Year 2007

General Instructions:
(i) The question paper consists of two sections, A and B. You are to attempt both the sections.
(ii) All questions are compulsory.
(iii) There is no overall choice. However, internal choice has been provided. 
(iv) All questions of Section A and all questions of Section B are to be attempted separately.
(v) Questions number 1 to 4 in Section A and 17 to 18 in Section B are short answer type questions. These questions carry one mark each.
(vi) Questions number 5 to 8 in Section A and 19 to 20 in Section B are short answer type questions and carry two marks each.
(vii) Questions number 9 to 14 in Section A and 21 to 23 in Section B are also short answer type questions and carry three marks each.
(viii) Questions number 15 to 16 in section A and question number 24 in section B are long answer type questions and carry  five marks each.
Q1 :

The pH values of three solutions A, B, and C having equal molar concentration are respectively 2.0, 7.0, and 13.0 at 298 K. Which of the three solutions represents an acid solution?


Answer :

A represents an acid solution. This is because the pH value of A is 2.0 and the pH value of an acids lies between 1 and 6.

Q2 :

Write the chemical formula of simplest ketone.


Answer :

Thechemical formula of simplest ketone, which is propanone, is.

Q3 :

Why is our galaxy called ‘Milky Way’?


Answer :

Our galaxy is called Milky Way because it appears white due to white light coming out of it.

Q4 :

If the distance between two electric charges is doubled, how much will the force exerting
between them change to
?


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Q5 :

State four characteristic features of ‘Dynamic Equilibrium’.


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Q6 :

What is Fehling’s reagent? What would you observe on heating formalin with Fehling’s reagent in a test tube?


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Q7 :

Distinguish between a ‘geosynchronous’ and a ‘polar’ satellite. What is the usual time period of a

(a) geosynchronous satellite
(b) polar satellite


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Q8 :

An electric heater is used on 220 V supply and takes a current of 3.4 A. Calculate (i) its power and (ii) its resistance, when it is in use.

(i)Power = Voltage × Current

= 220 × 3.4

= 748 Watt

(ii)Power = Voltage 2/ Resistance

P = V2/R

R = V2/P = 2202/ 748 = 64.71 Ω


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Q9 :

What is ‘Plaster of Paris’ chemically? How is it obtained from gypsum? Write the condition and chemical equation involved in its manufacture.


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Q10 :

Define the term, ‘allotropy’. In which kind of properties are the two allotropes of an element (i) similar, (ii) different? How can the two allotropes of sulphur be distinguished from one another?


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Q11 :

Give reasons for the following:

(a) Alcohol supplied for industrial purposes is mixed with poisonous substances such as copper sulphate.

(b) The reaction is classified as a decarboxylation reaction.

(c) Formalin is used for preserving biological specimens.


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Q12 :

A convex mirror used on a bus has a focal length of 200 cm. If a scooter is located at 400 cm from this mirror, find the position, nature and magnification of the image formed in the mirror.


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Q13 :

(a) What is a ‘solar cell’?
(b) Why is biogas considered an ideal fuel for domestic use?
(c) Name a device in which controlled chain reaction is used.


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Q14 :

(a) Define the term ‘electroplating’.

(b) With a labelled diagram describe an activity to show copper plating on a metal spoon.


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Q15 :

(a) Write the name and formula of the main ore ofaluminium.
(b) What is alumina? Which reducing agent is used for the reduction of alumina?
(c) Draw a diagram of the electrolytic cell used in the reduction of alumina. Label anode and cathode on it.
(d) Why is alumina dissolved in cryolite?

OR

(a) What is an alloy? How is an alloy made?
(b) Name an alloy
(i) which has a lower melting point than its constituents
(ii) which is more hard, tough and strong than its constituents
(c) Name the constituents of the alloy ‘Magnalium’. Write its two uses.


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Q16 :

Name the four common defects of vision and state the cause of each defect. A person cannot see distinctly objects placed beyond 2 metres. State the nature and focal length of the lens which could be used to correct this defect.

OR

(a) Describe with diagram an experiment to show that a force is exerted on a current carrying conductor when placed perpendicular in a magnetic field.

(b) State the rule to find the direction of the force exerted on a current carrying conductor in a magnetic field.


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Q17 :

What is meant by ‘translocation’ with respect to transport in plants?


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Q18 :

What is a ‘ganglion’?


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Q19 :

Anil has blood group ‘A’ while Om has blood group ‘O’.
(a) Persons of which blood group (s) can receive blood from (i) Anil and (ii) Om?
(b) Who can donate blood to (i) Anil and (ii) Om?

OR

Draw the human heart and label (i) Aorta, (ii) Coronary artery, (iii) pulmonary trunk and (iv) superior vena cava.


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Q20 :

What is autonomic nervous system? Name the subsystems in which it is subdivided.


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Q21 :

(a) How is the process of binary fission different from budding?

(b) What is grafting?

(c) List two advantages of vegetative propagation.

OR

Draw a diagram to illustrate fertilisation in a flowering plant and label the following in it:

(a) Pollen grains

(b) Ovule


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Q22 :

How is the sex of the offspring determined in the zygote? Explain.


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Q23 :

 Distinguish between ‘Conservation’ and ‘Preservation’. Suggest any four practices which may help in protecting our environment.


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Q24 :

(a) Draw the respiratory system of human beings.

(b) Label the following on the diagram drawn:
Larynx, Trachea, Primary Bronchus, Lungs

(c) What happens to the carbon dioxide which collects in human tissues?


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10th Science Paper Solutions Set 3 : CBSE Delhi Previous Year 2013 will be available online in PDF book soon. The solutions are absolutely Free. Soon you will be able to download the solutions.