Board Paper of Class 10 2009 Science (SET 2) - 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
What happens when a small piece of sodium is dropped into ethanol?VIEW SOLUTION
- Question 2
Which one of these has a higher concentration of H+ ions?
1 M HCl or 1 M CH3COOHVIEW SOLUTION
- Question 3
In electrolysis of water, why is the volume of gas collected over one electrode double that of gas collected over the other electrode?VIEW SOLUTION
- Question 4
State the rule which gives the direction of magnetic field associated with a current-carrying conductor.VIEW SOLUTION
- Question 5
Define the term ‘induced current’.VIEW SOLUTION
- Question 6
Draw a schematic diagram of an electric circuit consisting of a battery of two cells each of 1.5 V, 5 Ω, 10 Ω and 15 Ω resistors and a plug key, all connected in series.VIEW SOLUTION
- Question 7
Crystals of copper sulphate are heated in a test tube for some time
(a) What is the colour of copper sulphate crystals
(i) before heating, and
(ii) after heating?
b) What is the source of liquid droplets seen on the inner upper side of the test tube during the heating?VIEW SOLUTION
- Question 8
(i) What is observed when a solution of potassium iodide is added to a solution of lead nitrate taken in a test tube?
(ii) What type of reaction is this?
(iii) Write a balanced chemical equation to represent the above reaction.VIEW SOLUTION
- Question 9
A lamp rated 100 W at 220 V is connected to the mains electric supply. What current is drawn from the supply line if the voltage is 220 V?VIEW SOLUTION
- Question 10
What is an electric circuit? Distinguish between an open and a closed circuit.VIEW SOLUTION
- Question 11
(a) What is a homologous series of substances?
(b) In an organic compound, which parts largely determine its physical and chemical properties?
(c) Write a chemical equation to represent the reaction of ethanol with acidified solution of potassium dichromate?VIEW SOLUTION
- Question 12
(a) What is meant by periodicity in properties of elements with reference to the periodic table?
(b) Why do all the elements of the same group have similar properties?
(c) How will the tendency to gain electrons change as we go from left to right across a period? Why?VIEW SOLUTION
- Question 13
(a) Define the term ‘coulomb’.
(b) State the relationship between the electric current, the charge moving through a conductor and the time of flow.
Calculate the charge passing through an electric bulb in 20 minutes if the value of current is 200 mA.VIEW SOLUTION
- Question 14
For which position of the object does a convex lens form a virtual and erect image? Explain with the help of a ray diagram.VIEW SOLUTION
- Question 15
(a) Distinguish between ionic and covalent compounds under the following properties:
(i) Strength of forces between constituent elements
(ii) Solubility of compounds in water
(iii) Electrical conduction in substances
(b) Explain how the following metals are obtained from their compounds by the reduction process:
(i) Metal M which is in the middle of the reactivity series.
(ii) Metal N which is high up in the reactivity series.
Give one example of each type
(a) Distinguish between ‘roasting’ and ‘calcination’. Which of these two is used for sulphide ores and why?
(b) Write a chemical equation to illustrate the use of aluminium for joining cracked railway lines.
(c) Name the anode, the cathode and the electrolyte used in the electrolytic refining of impure copper.VIEW SOLUTION
- Question 16
The eye lens is composed of fibrous, jelly-type material. The curvature of the eye lens can be adjusted to a certain level with the aid of ciliary muscles. A change in the curvature of the eye lens can change its focal length. The eye lens becomes thin, and the focal length increases when the muscles of the eyes are relaxed. The objects at a distance can be viewed clearly when the focal length increases. But sometimes, the eye may gradually lose its power of accommodation and the person cannot see the objects distinctly and comfortably. It is called the defects in vision of the person. There are mainly three common refractive defects of vision. These are myopia (near-sightedness) , hypermetropia (far-sightedness) and presbyopia. These defects can be corrected by the use of spherical lenses of suitable focal length.
(a) What is myopia?
(b) State the two causes of myopia.
(c) With the help of labelled ray diagram, show:
(i) the eye defect myopia.
(ii) correction of myopia using a lens.
(d) Why is the normal eye unable to focus on an object placed within 10 cm from the eye?VIEW SOLUTION
- Question 17
Why are green plants called ‘Producers’?VIEW SOLUTION
- Question 18
Why is DNA copying an essential part of the process of reproduction?VIEW SOLUTION
- Question 19
Which compounds are responsible for the depletion of ozone layer?VIEW SOLUTION
- Question 20
Describe how hydro-energy can be converted into electrical energy. Write any two limitations of hydro-energy.VIEW SOLUTION
- Question 21
How is charcoal obtained from wood? Why is charcoal considered a better fuel than wood?VIEW SOLUTION
- Question 22
Describe the role of the following in human beings:
(i) Seminal vesicles
(ii) Prostate glandVIEW SOLUTION
- Question 23
An environmentalist on visit to your school suggested the use of three R’s to save the environment. Explain what he meant by three R’s and how you would follow his advice at home.VIEW SOLUTION
- Question 24
What is Chipko movement? Why should we conserve forests?VIEW SOLUTION
- Question 25
Explain how the sex of the child is determined at the time of conception in human beings.VIEW SOLUTION
- Question 26
What is ‘hydrotropism’? Describe an experiment to demonstrate ‘hydrotropism’’.VIEW SOLUTION
- Question 27
(a) Draw a sectional view of the human heart and label on it Aorta, Pulmonary arteries, Vena cava, Left ventricle.
(b) Why is double circulation of blood necessary in human beings?