10th Science Paper Solutions Set 1 : CBSE Delhi Previous Year 2009

General Instructions:
(i) The question paper comprises 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 in all the three questions of five marks category. Only one option in such questions is to be attempted
(iv) All questions of Section A and all questions of Section B are to be attempted separately
(v) Questions number 1 to 6 in Section A and 17 to 19 in Section B are short answer type questions. These questions carry one mark each
(vi) Questions number 7 to 10 in Section A and 20 to 24 in Section B are short answer type questions and carry two marks each
(vii) Questions number 11 to 14 in Section A and 25 and 26 in Section B are also short answer type questions and carry three marks each
(viii) Questions number 15 and 16 in section A and question number 27 in section B are long answer type questions and carry five marks each
Q1 :

Balance the following chemical equation:

Pb(NO3)2(s) PbO(s) + NO2(g) + O2(g)


Answer :

The balanced chemical equation for the given reaction is:

Q2 :

Fresh milk has a pH of 6. When it changes into curd (yogurt) will its pH value increase or decrease? Why?


Answer :

The pH value of milk decreases when it changes into curd. This is because curd contains lactic acid, which is acidic in nature. Acidic substances have pH values less than 7 and that of neutral substances is equal to seven. As the pH of milk is closer to 7 (6), the pH of milk will decrease when it changes into curd.

Q3 :

Name a reducing agent that may be used to obtain manganese from manganese dioxide.


Answer :

Aluminium (Al) is a reducing agent that may be used for obtaining manganese from manganese dioxide.

Q4 :

Why does a ray of light bend when it travels from one medium into another?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q5 :

Draw the given diagram in your answer book and complete it for the path of ray of light beyond the lens.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q6 :

Why does sky look blue on a clear day?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q7 :

A compound which is prepared from gypsum has the property of hardening when mixed with a proper quantity of water. Identify the compound. Write the chemical equation for its preparation. For what purpose is it used in hospitals?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q8 :

(a) What is the colour of ferrous sulphate crystals? How does this colour change after heating?

(b) Name the products formed on strongly heating ferrous sulphate crystals.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q9 :

What is the minimum number of rays required for locating the image formed by a concave mirror for an object? Draw a ray diagram to show the formation of a virtual image by a concave mirror.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q10 :

A piece of wire of resistance 20 Ωis drawn out so that its length is increased to twice its original length. Calculate the resistance of the wire in the new situation.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q11 :

What is meant by ‘rusting’? With labelled diagrams describe an activity to find out the conditions under which iron rusts.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q12 :

Give reasons for the following observations:

(a) The element carbon forms a very large number of compounds.

(b) Air holes of a gas burner have to be adjusted when the heated vessels get blackened by the flame.

(c) Use of synthetic detergents causes pollution of water.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q13 :

What is hypermetropia? State the two causes of hypermetropia. With the help of ray diagrams, show:

(i) the eye-defect hypermetropia (ii) correction of hypermetropia by using a lens


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q14 :

Two resistors, with resistances 5 Ωand 10 Ωrespectively are to be connected to a battery of emf 6 V so as to obtain:

(i) minimum current flowing (ii) maximum current flowing

(a) How will you connect the resistances in each case?

(b) Calculate the strength of the total current in the circuit in the two cases.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q15 :

(a) Which two criteria did Mendeleev use to classify the elements in his periodic table?

(b) State Mendeleev’s periodic law.

(c) Why could no fixed position be given to hydrogen in Mendeleev’s periodic table?

(d) How and why does the atomic size vary as you go:

(i) from left to right along a period?

(ii) down a group?

OR

(a) Why did Mendeleev have gaps in his periodic table?

(b) State any three limitations of Mendeleev’s classification.

(c) How does electronic configurations of atoms change in a period with increase in atomic number?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q16 :

(a) What is a magnetic field? How can the direction of magnetic field lines at a placed by determined?

(b) State the rule for the direction of the magnetic field produced around a current carrying conductor. Draw a sketch of the pattern of field lines due to a current carrying conductor. Draw a sketch of the pattern of filed lines due to a current flowing through a straight conductor.

OR

(a) What is a solenoid? Draw a sketch of the pattern of field lines of the magnetic field through and around a current carrying solenoid.

(b) Consider a circular loop of a wire lying in the plane of the table. Let the current pass through the loop clockwise. Apply the right hand rule to find out the direction of the magnetic field inside and outside the loop.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q17 :

What are the two main components of our environment? 


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q18 :

What will happen to a plant if its xylem is removed?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q19 :

Name two tissues that provide control and coordination in multicellular animals.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q20 :

What are natural resources? State two factors that work against an equitable distribution of these resources.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q21 :

What is water harvesting? Mention any two water harvesting structures.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q22 :

What are ‘nastic’ and ‘curvature’ movements? Give one example of each.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q23 :

What is biogas? Why is biogas considered an ideal fuel for domestic use?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q24 :

(a) Distinguish between renewable and non-renewable sources of energy.

(b) Choose the renewable sources of energy from the following list:

Coal, biogas, sun, natural gas


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q25 :

Explain analogous organs and homologous organs. Identify the analogous and homologous organs amongst the following:

Wings of an insect, wings of a bat, forelimbs of frog, forelimbs of a human.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q26 :

(a) Explain the terms:

(i) implantation (ii) Placenta

(b) What is the average duration of human pregnancy?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q27 :

(a) Draw a diagram of human alimentary canal and label on it.

Oesophagus, Gallbladder, Liver and Pancreas.

(b) Explain the statement, ‘Bile does not contain any enzyme but it is essential for digestion’

OR

(a) Draw a diagram of excretory system in human beings and label on it: 

Aorta, vena cava, urinary bladder, urethra.

(b) List two vital functions of the kidney 


Answer :

Please Register/Login to get access to all solutions Facebook Login

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.