10th Science Paper Solutions Set 1 : CBSE Delhi 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 :

Classify the following reactions into slow and fast reaction:

(i) Reaction between an acid and a base

(ii) Rusting of iron


Answer :

(i) Reaction between an acid and a base is a fast reaction.

(ii) Rusting of iron is a slow reaction.

Q2 :

Give the names of the functional groups

(i) — CHO
           |
(ii) — C=O


Answer :

(i) Aldehydic group

(ii) Ketonic group

Q3 :

What is a galaxy?


Answer :

Any large collection of stars that can be recognised as a distinct physical entity is called a galaxy.

Q4 :

 What is the S.I. unit of electric potential?


Answer :

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Q5 :

(a) Give Arrhenius definition of an acid and a base.

(b) Choose strong acid and strong base from the following:
CH3COOH, NH4OH, KOH, HCl


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Q6 :

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


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Q7 :

Distinguish between polar and equatorial orbits for artificial satellites. Illustrate the two orbits on a diagram.


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Q8 :

An electric iron has a rating of 750 W, 220 V. Calculate

(i) current passing through it, and

(ii) its resistance, when in use


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Q9 :

Name the raw materials that are required for the manufacture of washing soda by Solvay process. Describe the chemical reactions involved in the process.


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Q10 :

What is ‘liquor ammonia’? Describe with a diagram, ‘Fountain Experiment’ to demonstrate the following properties of ammonia:

(i) high solubility in water

(ii) its alkaline nature


Answer :

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Q11 :

Give reasons for the following:

(i) A peculiar smell is observed near the preserved specimens in biology laboratory.

(ii) Methanal undergoes addition reaction with hydrogen cyanide.

(iii) Propanone can be used as a nail polish remover.


Answer :

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Q12 :

A concave lens has focal length of 20 cm. At what distance from the lens can a 5 cm tall object be placed so that it forms an image at 15 cm from the lens? Also calculate the size of the image formed.


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Q13 :

(a) Why is the Solar Cooker box covered with a plane glass plate?

(b) Why is energy of water flowing in a river considered to be an indirect form of solar energy?

(c) How is the fission of nucleus brought about?


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Q14 :

(a) What is meant by ‘Electric Resistance’ of a conductor?

(b) A wire of length L and resistance R is stretched so that its length is doubled and the area of cross-section is halved. How will its:

(i) resistance change

(ii) resistivity change


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Q15 :

(a) Name one main ore of Aluminium. Write its formula. Which two main impurities are associated with this ore?

(b) Describe with chemical equations, the method employed for the enrichment of the above named ore.

OR

(a) Why is sulphuric acid called ‘King of Chemicals’?

(b) Describe the three chemical reactions that take place during the conversion of sulphur dioxide to sulphuric acid in the ‘Contact Process’.

(c) Why should water be never added dropwise to concentrated sulphuric acid?


Answer :

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Q16 :

Define the term, ‘Critical Angle’. What is meant by ‘total internal reflection’? State two essential conditions for total internal reflection to take place. With the help of a ray diagram, illustrate an application of total internal reflection.

OR

(a) What is meant by a ‘magnetic field’?

(b) How is the direction of magnetic field at a point determined?

(c) Describe an activity to demonstrate the direction of the magnetic field generated around a current carrying conductor.

(d) What is the direction of magnetic field at the centre of a current carrying circular loop?


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Q17 :

Name the term for transport of food from leaves to other parts of the plant.


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Q18 :

What is a neuron?


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Q19 :

State the two vital functions of the human kidney. Name the procedure used in the working of artificial kidney.


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Q20 :

Name the two hormones secreted by pancreas. Write one function of each hormone named.


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Q21 :

(a) What is fertilisation? Distinguish between external fertilisation and internal fertilisation.

(b) What is the site of fertilisation in human beings?


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Q22 :

Define the terms:

(i) Analogous organs

(ii) Vestigial organ

(iii) Sex chromosome


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Q23 :

(a) What is ‘environmental pollution’?

(b) Distinguish between biodegradable and non-biodegradable pollutants.

(c) Choose the biodegradable pollutants from the list given below:
Sewage, DDT, radioactive waste, agricultural waste

OR

Suggest three ways to maintain a balance between environment and development to survive.


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Q24 :

(a) Draw a diagram of a ‘palisade cell’.

(b) Label vacuole, chloroplast, cell wall, and cytoplasm on the diagram drawn.

(c) Name the two stages in photosynthesis.


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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.