Board Paper of Class 10 2009 Science Delhi(SET 1) - Solutions
(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
- Question 1
Balance the following chemical equation:
Pb(NO3)2(s) PbO(s) + NO2(g) + O2 (g)VIEW SOLUTION
- Question 2
Fresh milk has a pH of 6. When it changes into curd (yogurt) will its pH value increase or decrease? Why?VIEW SOLUTION
- Question 3
Name a reducing agent that may be used to obtain manganese from manganese dioxide.VIEW SOLUTION
- Question 4
Why does a ray of light bend when it travels from one medium into another?VIEW SOLUTION
- Question 5
Draw the given diagram in your answer book and complete it for the path of ray of light beyond the lens.
- Question 6
Why does sky look blue on a clear day?VIEW SOLUTION
- Question 7
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?VIEW SOLUTION
- Question 8
(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.VIEW SOLUTION
- Question 9
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.VIEW SOLUTION
- Question 10
A piece of wire of resistance 20 Ω is drawn out so that its length is increased to twice its original length. Calculate the resistance of the wire in the new situation.VIEW SOLUTION
- Question 11
What is meant by ‘rusting’? With labelled diagrams describe an activity to find out the conditions under which iron rusts.VIEW SOLUTION
- Question 12
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.VIEW SOLUTION
- Question 13
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 lensVIEW SOLUTION
- Question 14
Two resistors, with resistances 5 Ω and 10 Ω respectively 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.VIEW SOLUTION
- Question 15
(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?
(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?VIEW SOLUTION
- Question 16
(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 field lines due to a current flowing through a straight conductor.
(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.VIEW SOLUTION
- Question 17
What are the two main components of our environment?VIEW SOLUTION
- Question 18
What will happen to a plant if its xylem is removed?VIEW SOLUTION
- Question 19
Name two tissues that provide control and coordination in multicellular animals.VIEW SOLUTION
- Question 20
What are natural resources? State two factors that work against an equitable distribution of these resources.VIEW SOLUTION
- Question 21
What is water harvesting? Mention any two water harvesting structures.VIEW SOLUTION
- Question 22
What are ‘nastic’ and ‘curvature’ movements? Give one example of each.VIEW SOLUTION
- Question 23
What is biogas? Why is biogas considered an ideal fuel for domestic use?VIEW SOLUTION
- Question 24
(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 gasVIEW SOLUTION
- Question 25
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.VIEW SOLUTION
- Question 26
(a) Explain the terms:
(i) implantation (ii) Placenta
(b) What is the average duration of human pregnancy?VIEW SOLUTION
- Question 27
(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’
(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 kidneyVIEW SOLUTION